1
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Reddy PD, Nordin LJ, Hughes LB, Preidl AK, Mukherjee K. Expanded Stability of Layered SnSe-PbSe Alloys and Evidence of Displacive Phase Transformation from Rocksalt in Heteroepitaxial Thin Films. ACS Nano 2024; 18:13437-13449. [PMID: 38717390 DOI: 10.1021/acsnano.4c04128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Bulk PbSnSe has a two-phase region, or miscibility gap, as the crystal changes from a van der Waals-bonded orthorhombic 2D layered structure in SnSe-rich compositions to the related 3D-bonded rocksalt structure in PbSe-rich compositions. This structural transition drives a large contrast in the electrical, optical, and thermal properties. We realize low temperature direct growth of epitaxial PbSnSe thin films on GaAs via molecular beam epitaxy using an in situ PbSe surface treatment and show a significantly reduced two-phase region by stabilizing the Pnma layered structure out to Pb0.45Sn0.55Se, beyond the bulk limit around Pb0.25Sn0.75Se at low temperatures. Pushing further, we directly access metastable two-phase films of layered and rocksalt grains that are nearly identical in composition around Pb0.50Sn0.50Se and entirely circumvent the miscibility gap. We present microstructural and compositional evidence for an incomplete displacive transformation from a rocksalt to layered structure in these films, which we speculate occurs during the sample cooling to room temperature after synthesis. In situ temperature-cycling experiments on a Pb0.58Sn0.42Se rocksalt film reproduce characteristic attributes of a displacive transition and show a modulation in electronic properties. We find well-defined orientation relationships between the phases formed and reveal unconventional strain relief mechanisms involved in the crystal structure transformation using transmission electron microscopy. Overall, our work adds a scalable thin film integration route to harness the dramatic contrast in material properties in PbSnSe across a potentially ultrafast crystalline-crystalline structural transition.
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Affiliation(s)
- Pooja D Reddy
- Department of Materials Science and Engineering, Stanford University, Stanford, California94306, United States
| | - Leland J Nordin
- Department of Materials Science and Engineering, Stanford University, Stanford, California94306, United States
| | - Lillian B Hughes
- Materials Department, University of California, Santa Barbara, California93106, United States
| | - Anna-Katharina Preidl
- Department of Materials Science and Engineering, Stanford University, Stanford, California94306, United States
| | - Kunal Mukherjee
- Department of Materials Science and Engineering, Stanford University, Stanford, California94306, United States
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2
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Sun W, Wang Z, Hao B, Yan S, Sun H, Gu Z, Deng Y, Nie Y. In Situ Preparation of Superconducting Infinite-Layer Nickelate Thin Films with Atomically Flat Surface. Adv Mater 2024:e2401342. [PMID: 38754479 DOI: 10.1002/adma.202401342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 04/24/2024] [Indexed: 05/18/2024]
Abstract
Since their discovery, the infinite-layer nickelates have been regarded as an appealing system for gaining deeper insights into high temperature superconductivity (HTSC). However, the synthesis of superconducting samples has been proved to be challenging. Here, we develop an ultrahigh vacuum (UHV) in situ reduction method using atomic hydrogen as reducing agent and apply it in lanthanum nickelate system. The reduction parameters, including the reduction temperature (TR) and hydrogen pressure (PH), are systematically explored. We found that the reduction window for achieving superconducting transition is quite wide, reaching nearly 80°C in TR and 3 orders of magnitude in PH when the reduction time is set to 30 mins. And there exists an optimal PH for achieving the highest Tc if both TR and reduction time are fixed. More prominently, as confirmed by atomic force microscopy and scanning transmission electron microscopy, the atomically flat surface can be preserved during the in situ reduction process, providing advantages over the ex situ CaH2 method for surface-sensitive experiments. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wenjie Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhichao Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Bo Hao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Shengjun Yan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Haoying Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhengbin Gu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Yu Deng
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Yuefeng Nie
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
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3
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Gao W, Zhi G, Zhou M, Niu T. Growth of Single Crystalline 2D Materials beyond Graphene on Non-metallic Substrates. Small 2024:e2311317. [PMID: 38712469 DOI: 10.1002/smll.202311317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/14/2024] [Indexed: 05/08/2024]
Abstract
The advent of 2D materials has ushered in the exploration of their synthesis, characterization and application. While plenty of 2D materials have been synthesized on various metallic substrates, interfacial interaction significantly affects their intrinsic electronic properties. Additionally, the complex transfer process presents further challenges. In this context, experimental efforts are devoted to the direct growth on technologically important semiconductor/insulator substrates. This review aims to uncover the effects of substrate on the growth of 2D materials. The focus is on non-metallic substrate used for epitaxial growth and how this highlights the necessity for phase engineering and advanced characterization at atomic scale. Special attention is paid to monoelemental 2D structures with topological properties. The conclusion is drawn through a discussion of the requirements for integrating 2D materials with current semiconductor-based technology and the unique properties of heterostructures based on 2D materials. Overall, this review describes how 2D materials can be fabricated directly on non-metallic substrates and the exploration of growth mechanism at atomic scale.
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Affiliation(s)
- Wenjin Gao
- Tianmushan Laboratory, Hangzhou, 310023, China
- Hangzhou International Innovation Institute, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
| | | | - Miao Zhou
- Tianmushan Laboratory, Hangzhou, 310023, China
- Hangzhou International Innovation Institute, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
| | - Tianchao Niu
- Hangzhou International Innovation Institute, Beihang University, Hangzhou, 311115, China
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4
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Al Hassan A, AlHumaidi M, Kalt J, Schneider R, Müller E, Anjum T, Khadiev A, Novikov DV, Pietsch U, Baumbach T. Bending and reverse bending during the fabrication of novel GaAs/(In,Ga)As/GaAs core-shell nanowires monitored by in situx-ray diffraction. Nanotechnology 2024; 35:295705. [PMID: 38631325 DOI: 10.1088/1361-6528/ad3fc1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/17/2024] [Indexed: 04/19/2024]
Abstract
We report on the fabrication of a novel design of GaAs/(In,Ga)As/GaAs radial nanowire heterostructures on a Si 111 substrate, where, for the first time, the growth of inhomogeneous shells on a lattice mismatched core results in straight nanowires instead of bent. Nanowire bending caused by axial tensile strain induced by the (In,Ga)As shell on the GaAs core is reversed by axial compressive strain caused by the GaAs outer shell on the (In,Ga)As shell. Progressive nanowire bending and reverse bending in addition to the axial strain evolution during the two processes are accessed byin situby x-ray diffraction. The diameter of the core, thicknesses of the shells, as well as the indium concentration and distribution within the (In,Ga)As quantum well are revealed by 2D energy dispersive x-ray spectroscopy using a transmission electron microscope. Shell(s) growth on one side of the core without substrate rotation results in planar-like radial heterostructures in the form of free standing straight nanowires.
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Affiliation(s)
- Ali Al Hassan
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Mahmoud AlHumaidi
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Kaiserstraße 12, D-76131 Karlsruhe, Germany
| | - Jochen Kalt
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Kaiserstraße 12, D-76131 Karlsruhe, Germany
| | - Reinhard Schneider
- Laboratory for Electron Microscopy, Karlsruhe Institute for Technology, D-76128 Karlsruhe, Germany
| | - Erich Müller
- Laboratory for Electron Microscopy, Karlsruhe Institute for Technology, D-76128 Karlsruhe, Germany
| | - Taseer Anjum
- Solid State Physics, University of Siegen, Walter-Flex Straße 3, D-57068, Siegen, Germany
| | - Azat Khadiev
- DESY Photon Science, Notkestr. 85, D-22607 Hamburg, Germany
| | | | - Ullrich Pietsch
- Solid State Physics, University of Siegen, Walter-Flex Straße 3, D-57068, Siegen, Germany
| | - Tilo Baumbach
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
- Laboratory for Applications of Synchrotron Radiation, Karlsruhe Institute of Technology, Kaiserstraße 12, D-76131 Karlsruhe, Germany
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Mellaerts S, Bellani C, Hsu WF, Binetti A, Schouteden K, Recaman-Payo M, Menghini M, Rubio-Zuazo J, López-Sánchez J, Seo JW, Houssa M, Locquet JP. Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V 2O 3 Films. ACS Appl Mater Interfaces 2024. [PMID: 38683636 DOI: 10.1021/acsami.3c18807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Dimensional confinement has shown to be an effective strategy to tune competing degrees of freedom in complex oxides. Here, we achieved atomic layered growth of trigonal vanadium sesquioxide (V2O3) by means of oxygen-assisted molecular beam epitaxy. This led to a series of high-quality epitaxial ultrathin V2O3 films down to unit cell thickness, enabling the study of the intrinsic electron correlations upon confinement. By electrical and optical measurements, we demonstrate a dimensional confinement-induced metal-insulator transition in these ultrathin films. We shed light on the Mott-Hubbard nature of this transition, revealing a vanishing quasiparticle weight as demonstrated by photoemission spectroscopy. Furthermore, we prove that dimensional confinement acts as an effective out-of-plane stress. This highlights the structural component of correlated oxides in a confined architecture, while opening an avenue to control both in-plane and out-of-plane lattice components by epitaxial strain and confinement, respectively.
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Affiliation(s)
- Simon Mellaerts
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Claudio Bellani
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
| | - Wei-Fan Hsu
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Alberto Binetti
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Koen Schouteden
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Maria Recaman-Payo
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
| | - Mariela Menghini
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- IMDEA Nanociencia, Calle Faraday 9, E29049 Madrid, Spain
| | - Juan Rubio-Zuazo
- BM25-SpLine, ESRF, 38043 Grenoble, France
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Madrid 28049, Spain
| | - Jesús López-Sánchez
- BM25-SpLine, ESRF, 38043 Grenoble, France
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Madrid 28049, Spain
- Departamento de Electrocerámica, Instituto de Cerámica y Vidrio - Consejo Superior de Investigaciones Científicas (ICV-CSIC), Calle Kelsen 5, Madrid 28049, Spain
| | - Jin Won Seo
- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, 3001 Leuven, Belgium
| | - Michel Houssa
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
- Imec, Kapeldreef 75, Leuven 3001, Belgium
| | - Jean-Pierre Locquet
- Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium
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6
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Liang W, Wei W, Han D, Ming M, Zhang J, Wang Z, Zhang X, Wang T, Zhang J. E-Band InAs Quantum Dot Micro-Disk Laser with Metamorphic InGaAs Layers Grown on GaAs/Si (001) Substrate. Materials (Basel) 2024; 17:1916. [PMID: 38673273 PMCID: PMC11051710 DOI: 10.3390/ma17081916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 04/28/2024]
Abstract
The direct growth of III-V quantum dot (QD) lasers on silicon substrate has been rapidly developing over the past decade and has been recognized as a promising method for achieving on-chip light sources in photonic integrated circuits (PICs). Up to date, O- and C/L-bands InAs QD lasers on Si have been extensively investigated, but as an extended telecommunication wavelength, the E-band QD lasers directly grown on Si substrates are not available yet. Here, we demonstrate the first E-band (1365 nm) InAs QD micro-disk lasers epitaxially grown on Si (001) substrates by using a III-V/IV hybrid dual-chamber molecular beam epitaxy (MBE) system. The micro-disk laser device on Si was characterized with an optical threshold power of 0.424 mW and quality factor (Q) of 1727.2 at 200 K. The results presented here indicate a path to on-chip silicon photonic telecom-transmitters.
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Affiliation(s)
- Wenqian Liang
- School of Physics, South China Normal University, Guangzhou 510631, China
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
| | - Wenqi Wei
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
| | - Dong Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ming Ming
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jieyin Zhang
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
| | - Zihao Wang
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xinding Zhang
- School of Physics, South China Normal University, Guangzhou 510631, China
| | - Ting Wang
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianjun Zhang
- Songshan Lake Materials Laboratory, Dongguan 523808, China; (W.W.)
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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7
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Dong J, Inbar HS, Dempsey CP, Engel AN, Palmstrøm CJ. Strain Solitons in an Epitaxially Strained van der Waals-like Material. Nano Lett 2024; 24:4493-4497. [PMID: 38498733 PMCID: PMC11036392 DOI: 10.1021/acs.nanolett.4c00382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 03/20/2024]
Abstract
Strain solitons are quasi-dislocations that form in van der Waals materials to relieve the energy associated with lattice or rotational mismatch. Novel electronic properties of strain solitons were predicted and observed. To date, strain solitons have been observed only in exfoliated crystals or mechanically strained crystals. The lack of a scalable approach toward the generation of strain solitons poses a significant challenge in the study of and use of their properties. Here, we report the formation of strain solitons with epitaxial growth of bismuth on InSb(111)B by molecular beam epitaxy. The morphology of the strain solitons for films of varying thickness is characterized with scanning tunneling microscopy, and the local strain state is determined from atomic resolution images. Bending in the solitons is attributed to interactions with the interface, and large angle bending is associated with edge dislocations. Our results enable the scalable generation of strain solitons.
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Affiliation(s)
- Jason
T. Dong
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Hadass S. Inbar
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Connor P. Dempsey
- Deparment
of Electrical and Computer Engineering, University of California, Santa
Barbara, California 93106, United States
| | - Aaron N. Engel
- Materials
Department, University of California, Santa Barbara, California 93106, United States
| | - Christopher J. Palmstrøm
- Materials
Department, University of California, Santa Barbara, California 93106, United States
- Deparment
of Electrical and Computer Engineering, University of California, Santa
Barbara, California 93106, United States
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8
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Cheng Y, Wang J, He Z, Chen M, Guo X, Deng B, Ye Q, Li S, Chen H, Sou IK, Wu S. Broadband Photodetection of Centimeter-Scale T-Phase Gallium Telluride Grown by Molecular Beam Epitaxy. ACS Appl Mater Interfaces 2024; 16:17881-17890. [PMID: 38537646 DOI: 10.1021/acsami.4c00461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Two-dimensional (2D) semiconductors have recently attracted considerable attention due to their promising applications in future integrated electronic and optoelectronic devices. Large-scale synthesis of high-quality 2D semiconductors is an increasingly essential requirement for practical applications, such as sensing, imaging, and communications. In this work, homogeneous 2D GaTe films on a centimeter scale are epitaxially grown on fluorphlogopite mica substrates by molecular beam epitaxy (MBE). The epitaxial GaTe thin films showed an atomically 2D layered lattice structure with a T phase, which has not been discovered in the GaTe geometric isomer. Furthermore, semiconducting behavior and high mobility above room temperature were found in T-GaTe epitaxial films, which are essential for application in semiconducting devices. The T-GaTe-based photodetectors demonstrated respectable photodetection performance with a responsivity of 13 mA/W and a fast response speed. By introducing monolayer graphene as the substrate, we successfully realized high-quality GaTe/graphene heterostructures. The performance has been significantly improved, such as the responsivity was enhanced more than 20 times. These results highlight a feasible scheme for exploring the crystal phase of 2D GaTe and realizing the controlled growth of GaTe films on large substrates, which could promote the development of broadband, high-performance, and large-scale photodetection applications.
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Affiliation(s)
- Yijun Cheng
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiali Wang
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhihao He
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Mingyi Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xinhao Guo
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Bo Deng
- Hangzhou Key Laboratory of Quantum Matter, Department of Physics, Hangzhou Normal University, Hangzhou 311121, China
| | - Quanlin Ye
- Hangzhou Key Laboratory of Quantum Matter, Department of Physics, Hangzhou Normal University, Hangzhou 311121, China
| | - Shuwei Li
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Huanjun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Iam Keong Sou
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Shuxiang Wu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
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9
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Shen C, Zhan W, Tang J, Wu Z, Xu B, Zhao C, Wang Z. Universal Deoxidation of Semiconductor Substrates Assisted by Machine Learning and Real-Time Feedback Control. ACS Appl Mater Interfaces 2024; 16:18213-18221. [PMID: 38554077 DOI: 10.1021/acsami.4c01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/01/2024]
Abstract
Substrate oxidation is inevitable when exposed to ambient atmosphere during semiconductor manufacturing, which is detrimental to the fabrication of state-of-the-art devices. Optimizing the deoxidation process in molecular beam epitaxy (MBE) for random substrates poses a multidimensional challenge and is sometimes controversial. Due to variations in substrates and growth processes, the determination of the deoxidation condition heavily relies on the individual's expertise, yielding inconsistent results. This study employs a machine learning model that integrates interpolation and vision transformer (Interpolation-ViT) techniques. The model utilizes reflection high-energy electron diffraction videos as input to predict the status of the substrate, enabling automated deoxidation within a controlled architecture for various substrates. Furthermore, we highlight the potential of models trained on data from specific MBE equipment to achieve high-accuracy deployment on different pieces of equipment. In contrast to traditional methods, our approach holds exceptional value, as it standardizes deoxidation temperatures across diverse equipment and substrates. This significantly advances the standardization of the semiconductor process. The concepts and methods presented are expected to revolutionize semiconductor manufacturing processes in the optoelectronic and microelectronic industries.
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Affiliation(s)
- Chao Shen
- School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046, China
- Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Wenkang Zhan
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101804, China
- Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Jian Tang
- School of Physical and Electronic Engineering, Yancheng Teachers University, Yancheng 224002, China
| | - Zhaofeng Wu
- School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046, China
| | - Bo Xu
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101804, China
- Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Chao Zhao
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101804, China
- Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Zhanguo Wang
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101804, China
- Laboratory of Solid State Optoelectronics Information Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
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10
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Nian L, Sun H, Wang Z, Xu D, Hao B, Yan S, Li Y, Zhou J, Deng Y, Hao Y, Nie Y. Sr 4Al 2O 7: A New Sacrificial Layer with High Water Dissolution Rate for the Synthesis of Freestanding Oxide Membranes. Adv Mater 2024; 36:e2307682. [PMID: 38238890 DOI: 10.1002/adma.202307682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 12/18/2023] [Indexed: 02/01/2024]
Abstract
Freestanding perovskite oxide membranes have drawn great attention recently since they offer exceptional structural tunability and stacking ability, providing new opportunities in fundamental research and potential device applications in silicon-based semiconductor technology. Among different types of sacrificial layers, the (Ca, Sr, Ba)3Al2O6 compounds are most widely used since they can be dissolved in water and prepare high-quality perovskite oxide membranes with clean and sharp surfaces and interfaces; However, the typical transfer process takes a long time (up to hours) in obtaining millimeter-size freestanding membranes, let alone realize wafer-scale samples with high yield. Here, a new member of the SrO-Al2O3 family, Sr4Al2O7 is introduced, and its high dissolution rate, ≈10 times higher than that of Sr3Al2O6 is demonstrated. The high-dissolution-rate of Sr4Al2O7 is most likely related to the more discrete Al-O networks and higher concentration of water-soluble Sr-O species in this compound. This work significantly facilitates the preparation of freestanding membranes and sheds light on the integration of multifunctional perovskite oxides in practical electronic devices.
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Affiliation(s)
- Leyan Nian
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
- Suzhou Laboratory, Suzhou, 215125, P. R. China
| | - Haoying Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Zhichao Wang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Duo Xu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Bo Hao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Shengjun Yan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yueying Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Jian Zhou
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yu Deng
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yufeng Hao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
| | - Yuefeng Nie
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China
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11
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Giparakis M, Windischhofer A, Isceri S, Schrenk W, Schwarz B, Strasser G, Andrews AM. Design and performance of GaSb-based quantum cascade detectors. Nanophotonics 2024; 13:1773-1780. [PMID: 38681680 PMCID: PMC11052536 DOI: 10.1515/nanoph-2023-0702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/21/2023] [Indexed: 05/01/2024]
Abstract
InAs/AlSb quantum cascade detectors (QCDs) grown strain-balanced on GaSb substrates are presented. This material system offers intrinsic performance-improving properties, like a low effective electron mass of the well material of 0.026 m 0, enhancing the optical transition strength, and a high conduction band offset of 2.28 eV, reducing the noise and allowing for high optical transition energies. InAs and AlSb strain balance each other on GaSb with an InAs:AlSb ratio of 0.96:1. To regain the freedom of a lattice-matched material system regarding the optimization of a QCD design, submonolayer InSb layers are introduced. With strain engineering, four different active regions between 3.65 and 5.5 µm were designed with InAs:AlSb thickness ratios of up to 2.8:1, and subsequently grown and characterized. This includes an optimized QCD design at 4.3 µm, with a room-temperature peak responsivity of 26.12 mA/W and a detectivity of 1.41 × 108 Jones. Additionally, all QCD designs exhibit higher-energy interband signals in the mid- to near-infrared, stemming from the InAs/AlSb type-II alignment and the narrow InAs band gap.
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Affiliation(s)
- Miriam Giparakis
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Andreas Windischhofer
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Stefania Isceri
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Werner Schrenk
- Center for Micro- and Nanostructures, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Benedikt Schwarz
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Gottfried Strasser
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
- Center for Micro- and Nanostructures, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
| | - Aaron Maxwell Andrews
- Institute of Solid State Electronics, TU Wien, Gußhausstraße 25, 1040Vienna, Austria
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12
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Arif O, Canal L, Ferrari E, Ferrari C, Lazzarini L, Nasi L, Paghi A, Heun S, Sorba L. Influence of an Overshoot Layer on the Morphological, Structural, Strain, and Transport Properties of InAs Quantum Wells. Nanomaterials (Basel) 2024; 14:592. [PMID: 38607126 PMCID: PMC11013858 DOI: 10.3390/nano14070592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
InAs quantum wells (QWs) are promising material systems due to their small effective mass, narrow bandgap, strong spin-orbit coupling, large g-factor, and transparent interface to superconductors. Therefore, they are promising candidates for the implementation of topological superconducting states. Despite this potential, the growth of InAs QWs with high crystal quality and well-controlled morphology remains challenging. Adding an overshoot layer at the end of the metamorphic buffer layer, i.e., a layer with a slightly larger lattice constant than the active region of the device, helps to overcome the residual strain and provides optimally relaxed lattice parameters for the QW. In this work, we systematically investigated the influence of overshoot layer thickness on the morphological, structural, strain, and transport properties of undoped InAs QWs on GaAs(100) substrates. Transmission electron microscopy reveals that the metamorphic buffer layer, which includes the overshoot layer, provides a misfit dislocation-free InAs QW active region. Moreover, the residual strain in the active region is compressive in the sample with a 200 nm-thick overshoot layer but tensile in samples with an overshoot layer thicker than 200 nm, and it saturates to a constant value for overshoot layer thicknesses above 350 nm. We found that electron mobility does not depend on the crystallographic directions. A maximum electron mobility of 6.07 × 105 cm2/Vs at 2.6 K with a carrier concentration of 2.31 × 1011 cm-2 in the sample with a 400 nm-thick overshoot layer has been obtained.
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Affiliation(s)
- Omer Arif
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy; (O.A.); (L.C.); (A.P.); (S.H.)
| | - Laura Canal
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy; (O.A.); (L.C.); (A.P.); (S.H.)
| | - Elena Ferrari
- Istituto dei Materiali per l’Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche (IMEM–CNR), Parco Area delle Scienze 37/A, I-43124 Parma, Italy; (E.F.); (C.F.); (L.L.); (L.N.)
| | - Claudio Ferrari
- Istituto dei Materiali per l’Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche (IMEM–CNR), Parco Area delle Scienze 37/A, I-43124 Parma, Italy; (E.F.); (C.F.); (L.L.); (L.N.)
| | - Laura Lazzarini
- Istituto dei Materiali per l’Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche (IMEM–CNR), Parco Area delle Scienze 37/A, I-43124 Parma, Italy; (E.F.); (C.F.); (L.L.); (L.N.)
| | - Lucia Nasi
- Istituto dei Materiali per l’Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche (IMEM–CNR), Parco Area delle Scienze 37/A, I-43124 Parma, Italy; (E.F.); (C.F.); (L.L.); (L.N.)
| | - Alessandro Paghi
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy; (O.A.); (L.C.); (A.P.); (S.H.)
| | - Stefan Heun
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy; (O.A.); (L.C.); (A.P.); (S.H.)
| | - Lucia Sorba
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza S. Silvestro 12, I-56127 Pisa, Italy; (O.A.); (L.C.); (A.P.); (S.H.)
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13
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Bonaventura E, Martella C, Macis S, Dhungana DS, Krotkus S, Heuken M, Lupi S, Molle A, Grazianetti C. Optical properties of two-dimensional tin nanosheets epitaxially grown on graphene. Nanotechnology 2024; 35:23LT01. [PMID: 38467059 DOI: 10.1088/1361-6528/ad3254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/10/2024] [Indexed: 03/13/2024]
Abstract
Heterostacks formed by combining two-dimensional materials show novel properties which are of great interest for new applications in electronics, photonics and even twistronics, the new emerging field born after the outstanding discoveries on twisted graphene. Here, we report the direct growth of tin nanosheets at the two-dimensional limit via molecular beam epitaxy on chemical vapor deposited graphene on Al2O3(0001). The mutual interaction between the tin nanosheets and graphene is evidenced by structural and chemical investigations. On the one hand, Raman spectroscopy indicates that graphene undergoes compressive strain after the tin growth, while no charge transfer is observed. On the other hand, chemical analysis shows that tin nanosheets interaction with sapphire is mediated by graphene avoiding the tin oxidation occurring in the direct growth on this substrate. Remarkably, optical measurements show that the absorption of tin nanosheets exhibits a graphene-like behavior with a strong absorption in the ultraviolet photon energy range, therein resulting in a different optical response compared to tin nanosheets on bare sapphire. The optical properties of ultra-thin tin films therefore represent an open and flexible playground for the absorption of light in a broad range of the electromagnetic spectrum and technologically relevant applications for photon harvesting and sensors.
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Affiliation(s)
- Eleonora Bonaventura
- CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy
- Dipartment of Materials Science, University of Milano-Bicocca, via R. Cozzi 55, Milano, Italy
| | - Christian Martella
- CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy
| | - Salvatore Macis
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Roma, Italy
| | - Daya S Dhungana
- CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy
| | | | | | - Stefano Lupi
- Department of Physics, Sapienza University, Piazzale Aldo Moro 5, Roma, Italy
- CNR-IOM, Q2 Building, Area Science Park, Basovizza-Trieste, Italy
| | - Alessandro Molle
- CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy
| | - Carlo Grazianetti
- CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy
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14
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Varshney S, Choo S, Thompson L, Yang Z, Shah J, Wen J, Koester SJ, Mkhoyan KA, McLeod AS, Jalan B. Hybrid Molecular Beam Epitaxy for Single-Crystalline Oxide Membranes with Binary Oxide Sacrificial Layers. ACS Nano 2024; 18:6348-6358. [PMID: 38314696 DOI: 10.1021/acsnano.3c11192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
The advancement in thin-film exfoliation for synthesizing oxide membranes has led to possibilities for creating artificially assembled heterostructures with structurally and chemically incompatible materials. The sacrificial layer method is a promising approach to exfoliate as-grown films from a compatible material system, allowing for their integration with dissimilar materials. Nonetheless, the conventional sacrificial layers often possess an intricate stoichiometry, thereby constraining their practicality and adaptability, particularly when considering techniques such as molecular beam epitaxy (MBE). This is where easy-to-grow binary alkaline-earth-metal oxides with a rock salt crystal structure are useful. These oxides, which include (Mg, Ca, Sr, Ba)O, can be used as a sacrificial layer covering a much broader range of lattice parameters compared to conventional sacrificial layers and are easily dissolvable in deionized water. In this study, we show the epitaxial growth of the single-crystalline perovskite SrTiO3 (STO) on sacrificial layers consisting of crystalline SrO, BaO, and Ba1-xCaxO films, employing a hybrid MBE method. Our results highlight the rapid (≤5 min) dissolution of the sacrificial layer when immersed in deionized water, facilitating the fabrication of millimeter-sized STO membranes. Using high-resolution X-ray diffraction, atomic-force microscopy, scanning transmission electron microscopy, impedance spectroscopy, and scattering-type near-field optical microscopy (SNOM), we demonstrate single-crystalline STO membranes with bulk-like intrinsic dielectric properties. The employment of alkaline earth metal oxides as sacrificial layers is likely to simplify membrane synthesis, particularly with MBE, thus expanding the research and application possibilities.
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Affiliation(s)
- Shivasheesh Varshney
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Sooho Choo
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Liam Thompson
- School of Physics and Astronomy, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Zhifei Yang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
- School of Physics and Astronomy, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Jay Shah
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Jiaxuan Wen
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Steven J Koester
- Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - K Andre Mkhoyan
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Alexander S McLeod
- School of Physics and Astronomy, University of Minnesota, Twin Cities, Minnesota 55455, United States
| | - Bharat Jalan
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, Minnesota 55455, United States
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15
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Zhu K, Cheng Y, Liao M, Chong SK, Zhang D, He K, Wang KL, Chang K, Deng P. Unveiling the Anomalous Hall Response of the Magnetic Structure Changes in the Epitaxial MnBi 2Te 4 Films. Nano Lett 2024; 24:2181-2187. [PMID: 38340079 PMCID: PMC10885191 DOI: 10.1021/acs.nanolett.3c04095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Recently discovered as an intrinsic antiferromagnetic topological insulator, MnBi2Te4 has attracted tremendous research interest, as it provides an ideal platform to explore the interplay between topological and magnetic orders. MnBi2Te4 displays distinct exotic topological phases that are inextricably linked to the different magnetic structures of the material. In this study, we conducted electrical transport measurements and systematically investigated the anomalous Hall response of epitaxial MnBi2Te4 films when subjected to an external magnetic field sweep, revealing the different magnetic structures stemming from the interplay of applied fields and the material's intrinsic antiferromagnetic (AFM) ordering. Our results demonstrate that the nonsquare anomalous Hall loop is a consequence of the distinct reversal processes within individual septuple layers. These findings shed light on the intricate magnetic structures in MnBi2Te4 and related materials, offering insights into understanding their transport properties and facilitating the implementation of AFM topological electronics.
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Affiliation(s)
- Kejing Zhu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Menghan Liao
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Su Kong Chong
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Ding Zhang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Ke He
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Kai Chang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Peng Deng
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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16
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Shiffa M, Dewes BT, Bradford J, Cottam ND, Cheng TS, Mellor CJ, Makarovskiy O, Rahman K, O'Shea JN, Beton PH, Novikov SV, Ben T, Gonzalez D, Xie J, Zhang L, Patanè A. Wafer-Scale Two-Dimensional Semiconductors for Deep UV Sensing. Small 2024; 20:e2305865. [PMID: 37798672 DOI: 10.1002/smll.202305865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/29/2023] [Indexed: 10/07/2023]
Abstract
2D semiconductors (2SEM) can transform many sectors, from information and communication technology to healthcare. To date, top-down approaches to their fabrication, such as exfoliation of bulk crystals by "scotch-tape," are widely used, but have limited prospects for precise engineering of functionalities and scalability. Here, a bottom-up technique based on epitaxy is used to demonstrate high-quality, wafer-scale 2SEM based on the wide band gap gallium selenide (GaSe) compound. GaSe layers of well-defined thickness are developed using a bespoke facility for the epitaxial growth and in situ studies of 2SEM. The dominant centrosymmetry and stacking of the individual van der Waals layers are verified by theory and experiment; their optical anisotropy and resonant absorption in the UV spectrum are exploited for photon sensing in the technological UV-C spectral range, offering a scalable route to deep-UV optoelectronics.
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Affiliation(s)
- Mustaqeem Shiffa
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Benjamin T Dewes
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan Bradford
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Nathan D Cottam
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Tin S Cheng
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Christopher J Mellor
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Oleg Makarovskiy
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Kazi Rahman
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - James N O'Shea
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter H Beton
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sergei V Novikov
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Teresa Ben
- University Research Institute on Electron Microscopy and Materials, IMEYMAT, Universidad de Cádiz, Cádiz, 11510, Spain
| | - David Gonzalez
- University Research Institute on Electron Microscopy and Materials, IMEYMAT, Universidad de Cádiz, Cádiz, 11510, Spain
| | - Jiahao Xie
- College of Materials Science and Engineering, Jilin University, Changchun, 130012, China
| | - Lijun Zhang
- College of Materials Science and Engineering, Jilin University, Changchun, 130012, China
| | - Amalia Patanè
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
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17
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Bai Y, Li Y, Luan J, Liu R, Song W, Chen Y, Ji PF, Zhang Q, Meng F, Tong B, Li L, Jiang Y, Gao Z, Gu L, Zhang J, Wang Y, Xue QK, He K, Feng Y, Feng X. Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown MnBi 2Te 4 thin films. Natl Sci Rev 2024; 11:nwad189. [PMID: 38213514 PMCID: PMC10776363 DOI: 10.1093/nsr/nwad189] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/29/2023] [Accepted: 05/16/2023] [Indexed: 01/13/2024] Open
Abstract
The intrinsic magnetic topological insulator MnBi2Te4 provides a feasible pathway to the high-temperature quantum anomalous Hall (QAH) effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4 thin flakes, it remains a big challenge to achieve molecular beam epitaxy (MBE)-grown MnBi2Te4 thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4 thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4 and to find a way out of the big difficulty in obtaining MnBi2Te4 samples showing quantized transport properties.
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Affiliation(s)
- Yunhe Bai
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Yuanzhao Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Jianli Luan
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Ruixuan Liu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Wenyu Song
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Yang Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Peng-Fei Ji
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Qinghua Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Fanqi Meng
- School of Materials Science and Engineering, Tsinghua University, Beijing100084, China
| | - Bingbing Tong
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Lin Li
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Yuying Jiang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
| | - Zongwei Gao
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Lin Gu
- School of Materials Science and Engineering, Tsinghua University, Beijing100084, China
| | - Jinsong Zhang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Hefei National Laboratory, Hefei230088, China
| | - Yayu Wang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Hefei National Laboratory, Hefei230088, China
| | - Qi-Kun Xue
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Southern University of Science and Technology, Shenzhen518055, China
| | - Ke He
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Hefei National Laboratory, Hefei230088, China
| | - Yang Feng
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
| | - Xiao Feng
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing100084, China
- Frontier Science Center for Quantum Information, Beijing100084, China
- Beijing Academy of Quantum Information Sciences, Beijing100193, China
- Hefei National Laboratory, Hefei230088, China
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18
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Lee S, Kwon YK, Kim M, Yi GC. Novel Polytype of III-VI Metal Chalcogenides Nano Crystals Realized in Epitaxially Grown InTe. Small 2024:e2308925. [PMID: 38268229 DOI: 10.1002/smll.202308925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/07/2023] [Indexed: 01/26/2024]
Abstract
III-VI metal chalcogenides have garnered considerable research attention as a novel group of layered van der Waals materials because of their exceptional physical properties and potential technological applications. Here, the epitaxial growth and stacking sequences of InTe is reported, an essential and intriguing material from III-VI metal chalcogenides. Aberration-corrected scanning transmission electron microscopy (STEM) is utilized to directly reveal the interlayer stacking modes and atomic structure, leading to a discussion of a new polytype. Furthermore, correlations between the stacking sequences and interlayer distances are substantiated by atomic-resolution STEM analysis, which offers evidence for strong interlayer coupling of the new polytype. It is proposed that layer-by-layer deposition is responsible for the formation of the unconventional stacking order, which is supported by ab initio density functional theory calculations. The results thus establish molecular beam epitaxy as a viable approach for synthesizing novel polytypes. The experimental validation of the InTe polytype here expands the family of materials in the III-VI metal chalcogenides while suggesting the possibility of new stacking sequences for known materials in this system.
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Affiliation(s)
- Sangmin Lee
- Department of Materials Science & Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Young-Kyun Kwon
- Department of Physics, Department of Information Display, and Research Institute for Basic Sciences, Kyung Hee University, Seoul, 02447, South Korea
| | - Miyoung Kim
- Department of Materials Science & Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Gyu-Chul Yi
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
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19
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Stramaglia F, Panchal G, Nolting F, Vaz CAF. Fully Magnetically Polarized Ultrathin La 0.8Sr 0.2MnO 3 Films. ACS Appl Mater Interfaces 2024; 16:4138-4149. [PMID: 38216138 PMCID: PMC10811626 DOI: 10.1021/acsami.3c14031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 01/14/2024]
Abstract
We report the observation of fully magnetically polarized ultrathin La0.8Sr0.2MnO3 films by using LaMnO3 and La0.45Sr0.55MnO3 buffer layers grown epitaxially on SrTiO3(001) substrates by molecular beam epitaxy. Specifically, we show that La0.8Sr0.2MnO3 films grown on 12-unit-cell LaMnO3 have bulk-like magnetic moments starting from a single unit cell thickness, while for the 15-unit-cell La0.45Sr0.55MnO3 buffer layer, the La0.8Sr0.2MnO3 transitions from an antiferromagnetic state to a fully spin-polarized ferromagnetic state at 4 unit cells. The magnetic results are confirmed by X-ray magnetic circular dichroism, while linear dichroic measurements carried out for the La0.8Sr0.2MnO3/La0.45Sr0.55MnO3 series show the presence of an orbital reorganization at the transition from the antiferromagnetic to ferromagnetic state corresponding to a change from a preferred in-plane orbital hole occupancy, characteristic of the A-type antiferromagnetic state of La0.45Sr0.55MnO3, to preferentially out of plane. We interpret our findings in terms of the different electronic charge transfers between the adjacent layers, confined to the unit cell in the case of insulating LaMnO3 and extended to a few unit cells in the case of conducting La0.45Sr0.55MnO3. Our work demonstrates an approach to growing ultrathin mixed-valence manganite films that are fully magnetically polarized from the single unit cell, paving the way to fully exploring the unique electronic properties of this class of strongly correlated oxide materials.
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Affiliation(s)
| | - Gyanendra Panchal
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Frithjof Nolting
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Carlos A. F. Vaz
- Swiss Light Source, Paul Scherrer Institut, Villigen 5232, Switzerland
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20
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Guillet T, Galceran R, Sierra JF, Belarre FJ, Ballesteros B, Costache MV, Dosenovic D, Okuno H, Marty A, Jamet M, Bonell F, Valenzuela SO. Spin-Orbit Torques and Magnetization Switching in (Bi,Sb) 2Te 3/Fe 3GeTe 2 Heterostructures Grown by Molecular Beam Epitaxy. Nano Lett 2024; 24:822-828. [PMID: 38263950 DOI: 10.1021/acs.nanolett.3c03291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Topological insulators (TIs) hold promise for manipulating the magnetization of a ferromagnet (FM) through the spin-orbit torque (SOT) mechanism. However, integrating TIs with conventional FMs often leads to significant device-to-device variations and a broad distribution of SOT magnitudes. In this work, we present a scalable approach to grow a full van der Waals FM/TI heterostructure by molecular beam epitaxy, combining the charge-compensated TI (Bi,Sb)2Te3 with 2D FM Fe3GeTe2 (FGT). Harmonic magnetotransport measurements reveal that the SOT efficiency exhibits a non-monotonic temperature dependence and experiences a substantial enhancement with a reduction of the FGT thickness to 2 monolayers. Our study further demonstrates that the magnetization of ultrathin FGT films can be switched with a current density of Jc ∼ 1010 A/m2, with minimal device-to-device variations compared to previous investigations involving traditional FMs.
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Affiliation(s)
- Thomas Guillet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Regina Galceran
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Juan F Sierra
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Francisco J Belarre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Belén Ballesteros
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Marius V Costache
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | | | - Hanako Okuno
- Univ. Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France
| | - Alain Marty
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Matthieu Jamet
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Frédéric Bonell
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08070 Barcelona, Spain
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21
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Antonelli T, Rajan A, Watson MD, Soltani S, Houghton J, Siemann GR, Zivanovic A, Bigi C, Edwards B, King PDC. Controlling the Charge Density Wave Transition in Single-Layer TiTe 2xSe 2(1-x) Alloys by Band Gap Engineering. Nano Lett 2024; 24:215-221. [PMID: 38117702 PMCID: PMC10786161 DOI: 10.1021/acs.nanolett.3c03776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/22/2023]
Abstract
Closing the band gap of a semiconductor into a semimetallic state gives a powerful potential route to tune the electronic energy gains that drive collective phases like charge density waves (CDWs) and excitonic insulator states. We explore this approach for the controversial CDW material monolayer (ML) TiSe2 by engineering its narrow band gap to the semimetallic limit of ML-TiTe2. Using molecular beam epitaxy, we demonstrate the growth of ML-TiTe2xSe2(1-x) alloys across the entire compositional range and unveil how the (2 × 2) CDW instability evolves through the normal state semiconductor-semimetal transition via in situ angle-resolved photoemission spectroscopy. Through model electronic structure calculations, we identify how this tunes the relative strength of excitonic and Peierls-like coupling, demonstrating band gap engineering as a powerful method for controlling the microscopic mechanisms underpinning the formation of collective states in two-dimensional materials.
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Affiliation(s)
- Tommaso Antonelli
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Akhil Rajan
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Matthew D. Watson
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | | | - Joe Houghton
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Gesa-Roxanne Siemann
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Andela Zivanovic
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Chiara Bigi
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Brendan Edwards
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
| | - Phil D. C. King
- SUPA, School of Physics and
AstronomyUniversity of St Andrews, St Andrews KY16 9SS, United Kingdom
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22
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Gao W, Dou W, Zhou D, Song B, Niu T, Hua C, Wee ATS, Zhou M. Epitaxial Growth of 2D Binary Phosphides. Small Methods 2024:e2301512. [PMID: 38175841 DOI: 10.1002/smtd.202301512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Indexed: 01/06/2024]
Abstract
Combinations of phosphorus with main group III, IV, and V elements are theoretically predicted to generate 2D binary phosphides with extraordinary properties and promising applications. However, experimental synthesis is significantly lacking. Here, a general approach for preparing 2D binary phosphides is reported using single crystalline surfaces containing the constituent element of target 2D materials as the substrate. To validate this, SnP3 and BiP, representing typical 2D binary phosphides, are successfully synthesized on Cu2 Sn and bismuthene, respectively. Scanning tunneling microscopy imaging reveals a hexagonal pattern of SnP3 on Cu2 Sn, while α-BiP can be epitaxially grown on the α-bismuthene domain on Cu2 Sb. First-principles calculations reveal that the formation of SnP3 on Cu2 Sn is associated with strong interface bonding and significant charge transfer, while α-BiP interacts weakly with α-bismuthene so that its semiconducting property is preserved. The study demonstrates an attractive avenue for the atomic-scale growth of binary 2D materials via substrate phase engineering.
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Affiliation(s)
- Wenjin Gao
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
| | - Wenzhen Dou
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
| | - Dechun Zhou
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
- Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Biyu Song
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
| | - Tianchao Niu
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
| | - Chenqiang Hua
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
| | - Andrew Thye Shen Wee
- Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Miao Zhou
- Collaborative Center for Physics and Chemistry, Institute of International Innovation, Beihang University, Hangzhou, 311115, China
- School of Physics, Beihang University, Beijing, 100191, China
- Tianmushan Laboratory, Hangzhou, 310023, China
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23
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Cecchi S, Momand J, Dragoni D, Abou El Kheir O, Fagiani F, Kriegner D, Rinaldi C, Arciprete F, Holý V, Kooi BJ, Bernasconi M, Calarco R. Thick Does the Trick: Genesis of Ferroelectricity in 2D GeTe-Rich (GeTe) m (Sb 2 Te 3 ) n Lamellae. Adv Sci (Weinh) 2024; 11:e2304785. [PMID: 37988708 PMCID: PMC10767439 DOI: 10.1002/advs.202304785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/28/2023] [Indexed: 11/23/2023]
Abstract
The possibility to engineer (GeTe)m (Sb2 Te3 )n phase-change materials to co-host ferroelectricity is extremely attractive. The combination of these functionalities holds great technological impact, potentially enabling the design of novel multifunctional devices. Here an experimental and theoretical study of epitaxial (GeTe)m (Sb2 Te3 )n with GeTe-rich composition is presented. These layered films feature a tunable distribution of (GeTe)m (Sb2 Te3 )1 blocks of different sizes. Breakthrough evidence of ferroelectric displacement in thick (GeTe)m (Sb2 Te3 )1 lamellae is provided. The density functional theory calculations suggest the formation of a tilted (GeTe)m slab sandwiched in GeTe-rich blocks. That is, the net ferroelectric polarization is confined almost in-plane, representing an unprecedented case between 2D and bulk ferroelectric materials. The ferroelectric behavior is confirmed by piezoresponse force microscopy and electroresistive measurements. The resilience of the quasi van der Waals character of the films, regardless of their composition, is also demonstrated. Hence, the material developed hereby gathers in a unique 2D platform the phase-change and ferroelectric switching properties, paving the way for the conception of innovative device architectures.
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Affiliation(s)
- Stefano Cecchi
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
- Paul‐Drude‐Institut für FestkörperelektronikLeibniz‐Institut im Forschungsverbund Berlin e.V.Hausvogteiplatz 5‐710117BerlinGermany
| | - Jamo Momand
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Daniele Dragoni
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Omar Abou El Kheir
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Federico Fagiani
- Dipartimento di FisicaPolitecnico di MilanoP.zza Leonardo da Vinci 3220133MilanoItaly
| | - Dominik Kriegner
- Institute of Solid State and Materials PhysicsTechnische Universität DresdenHelmholtzstr. 1001069DresdenGermany
- Institute of PhysicsCzech Academy of SciencesCukrovarnická 10/11216200Praha 6Czech Republic
| | - Christian Rinaldi
- Dipartimento di FisicaPolitecnico di MilanoP.zza Leonardo da Vinci 3220133MilanoItaly
| | - Fabrizio Arciprete
- Dipartimento di FisicaUniversità di Roma “Tor Vergata”Via della Ricerca Scientifica 100133RomeItaly
| | - Vaclav Holý
- Department of Condensed Matter PhysicsFaculty of Mathematics and PhysicsCharles University, Ke Karlovu 512116PrahaCzech Republic
- Institute of Condensed Matter PhysicsFaculty of ScienceMasaryk UniversityKotlářská 2611 37BrnoCzech Republic
| | - Bart J. Kooi
- Zernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747 AGGroningenThe Netherlands
| | - Marco Bernasconi
- Department of Materials ScienceUniversity of Milano‐Bicoccavia R. Cozzi 5520125MilanoItaly
| | - Raffaella Calarco
- Paul‐Drude‐Institut für FestkörperelektronikLeibniz‐Institut im Forschungsverbund Berlin e.V.Hausvogteiplatz 5‐710117BerlinGermany
- CNR Institute for Microelectronics and Microsystems–IMMConsiglio Nazionale delle RicercheVia del Fosso del Cavaliere 10000133RomaItaly
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24
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Feng R, Wang W, Bao C, Zhang Z, Wang F, Zhang H, Yao J, Xu Y, Yu P, Ji SH, Si C, Zhou S. Selective Control of Phases and Electronic Structures of Monolayer TaTe 2. Adv Mater 2024; 36:e2302297. [PMID: 37565385 DOI: 10.1002/adma.202302297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 08/01/2023] [Indexed: 08/12/2023]
Abstract
Transition metal dichalcogenide (TMDC) films exhibit rich phases and superstructures, which can be controlled by the growth conditions as well as post-growth annealing treatment. Here, the selective growth of monolayer TaTe2 films with different phases as well as superstructures using molecular beam epitaxy (MBE) is reported. Monolayer 1H-TaTe2 and 1T-TaTe2 films can be selectively controlled by varying the growth temperature, and their different electronic structures are revealed through the combination of angle-resolved photoemission spectroscopy measurements (ARPES) and first-principles calculations. Moreover, post-growth annealing of the 1H-TaTe2 film further leads to a transition from a19 × 19 $\sqrt {19}{\times }\sqrt {19}$ superstructure to a new 2 × 2 superstructure, where two gaps are observed in the electronic structure and persist up to room temperature. First-principles calculations reveal the role of the phonon instability in the formation of superstructures and the effect of local atomic distortions on the modified electronic structures. This work demonstrates the manipulation of the rich phases and superstructures of monolayer TaTe2 films by controlling the growth kinetics and post-growth annealing.
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Affiliation(s)
- Runfa Feng
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Wei Wang
- School of Materials Science and Engineering, Beihang University, Beijing, 100084, P. R. China
| | - Changhua Bao
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Zichun Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Fei Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Hongyun Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Junjie Yao
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Yong Xu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing, 100084, P. R. China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan
| | - Pu Yu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing, 100084, P. R. China
| | - Shuai-Hua Ji
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
| | - Chen Si
- School of Materials Science and Engineering, Beihang University, Beijing, 100084, P. R. China
| | - Shuyun Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
- Frontier Science Center for Quantum Information, Beijing, 100084, P. R. China
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25
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Altena M, Jansen T, Tsvetanova M, Brinkman A. Phase Separation Prevents the Synthesis of VBi 2Te 4 by Molecular Beam Epitaxy. Nanomaterials (Basel) 2023; 14:87. [PMID: 38202542 PMCID: PMC10780430 DOI: 10.3390/nano14010087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/17/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024]
Abstract
Intrinsic magnetic topological insulators (IMTIs) have a non-trivial band topology in combination with magnetic order. This potentially leads to fascinating states of matter, such as quantum anomalous Hall (QAH) insulators and axion insulators. One of the theoretically predicted IMTIs is VBi2Te4, but experimental evidence of this material is lacking so far. Here, we report on our attempts to synthesise VBi2Te4 by molecular beam epitaxy (MBE). X-ray diffraction reveals that in the thermodynamic phase space reachable by MBE, there is no region where VBi2Te4 is stably synthesised. Moreover, scanning transmission electron microscopy shows a clear phase separation to Bi2Te3 and VTe2 instead of the formation of VBi2Te4. We suggest the phase instability to be due to either the large lattice mismatch between VTe2 and Bi2Te3 or the unfavourable valence state of vanadium.
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Affiliation(s)
- Marieke Altena
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Thies Jansen
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
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26
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Manzo S, Su K, Arnold MS, Kawasaki JK. Nucleation Selectivity and Lateral Coalescence of GaAs over Graphene on Ge(111). ACS Appl Mater Interfaces 2023; 15:59905-59911. [PMID: 38084509 DOI: 10.1021/acsami.3c13600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
We use epitaxial lateral overgrowth (ELO) to produce semimetallic graphene nanostructures embedded in a semiconducting GaAs matrix for potential applications in plasmonics, THz generation and detection, and tunnel junctions in multijunction solar cells. We show that (1) the combination of low sticking coefficient and fast surface diffusion on graphene enhances nucleation selectivity at exposed regions of the substrate and (2) high growth temperatures favor efficient lateral overgrowth, coalescence, and planarization of epitaxial GaAs films over the graphene nanostructures. Our work provides a more complete understanding of ELO using graphene masks, as opposed to more conventional dielectric masks, and enables new types of metal/semiconductor nanocomposites.
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Affiliation(s)
- Sebastian Manzo
- Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Katherine Su
- Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Michael S Arnold
- Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jason K Kawasaki
- Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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27
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Zhao YF, Zhang R, Sun ZT, Zhou LJ, Zhuo D, Yan ZJ, Yi H, Wang K, Chan MHW, Liu CX, Law KT, Chang CZ. 3D Quantum Anomalous Hall Effect in Magnetic Topological Insulator Trilayers of Hundred-Nanometer Thickness. Adv Mater 2023:e2310249. [PMID: 38118065 DOI: 10.1002/adma.202310249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/07/2023] [Indexed: 12/22/2023]
Abstract
Magnetic topological states refer to a class of exotic phases in magnetic materials with the non-trivial topological property determined by magnetic spin configurations. An example of such states is the quantum anomalous Hall (QAH) state, which is a zero magnetic field manifestation of the quantum Hall effect. Current research in this direction focuses on QAH insulators with a thickness of less than 10 nm. Here, molecular beam epitaxy (MBE) is employed to synthesize magnetic TI trilayers with a thickness of up to ≈106 nm. It is found that these samples exhibit well-quantized Hall resistance and vanishing longitudinal resistance at zero magnetic field. By varying the magnetic dopants, gate voltages, temperature, and external magnetic fields, the properties of these thick QAH insulators are examined and the robustness of the 3D QAH effect is demonstrated. The realization of the well-quantized 3D QAH effect indicates that the nonchiral side surface states of the thick magnetic TI trilayers are gapped and thus do not affect the QAH quantization. The 3D QAH insulators of hundred-nanometer thickness provide a promising platform for the exploration of fundamental physics, including axion physics and image magnetic monopole, and the advancement of electronic and spintronic devices to circumvent Moore's law.
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Affiliation(s)
- Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ruoxi Zhang
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zi-Ting Sun
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, 999077, China
| | - Ling-Jie Zhou
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Deyi Zhuo
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zi-Jie Yan
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hemian Yi
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ke Wang
- Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Chao-Xing Liu
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - K T Law
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, 999077, China
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, PA, 16802, USA
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Hoenk ME, Jewell AD, Kyne G, Hennessy J, Jones T, Shapiro C, Bush N, Nikzad S, Morris D, Lawrie K, Skottfelt J. Surface Passivation by Quantum Exclusion: On the Quantum Efficiency and Stability of Delta-Doped CCDs and CMOS Image Sensors in Space. Sensors (Basel) 2023; 23:9857. [PMID: 38139703 PMCID: PMC10747789 DOI: 10.3390/s23249857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/28/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023]
Abstract
Radiation-induced damage and instabilities in back-illuminated silicon detectors have proved to be challenging in multiple NASA and commercial applications. In this paper, we develop a model of detector quantum efficiency (QE) as a function of Si-SiO2 interface and oxide trap densities to analyze the performance of silicon detectors and explore the requirements for stable, radiation-hardened surface passivation. By analyzing QE data acquired before, during, and after, exposure to damaging UV radiation, we explore the physical and chemical mechanisms underlying UV-induced surface damage, variable surface charge, QE, and stability in ion-implanted and delta-doped detectors. Delta-doped CCD and CMOS image sensors are shown to be uniquely hardened against surface damage caused by ionizing radiation, enabling the stability and photometric accuracy required by NASA for exoplanet science and time domain astronomy.
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Affiliation(s)
- Michael E. Hoenk
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - April D. Jewell
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - Gillian Kyne
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - John Hennessy
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - Todd Jones
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - Charles Shapiro
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - Nathan Bush
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - Shouleh Nikzad
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA; (A.D.J.); (G.K.); (J.H.); (T.J.); (N.B.); (S.N.)
| | - David Morris
- Teledyne e2v, Chelmsford CM1 2QU, UK; (D.M.); (K.L.)
| | | | - Jesper Skottfelt
- Centre for Electronic Imaging, School of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK;
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29
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Yeon E, Woo S, Chu RJ, Lee IH, Jang HW, Jung D, Choi WJ. Reduction of Structural Defects in the GaSb Buffer Layer on (001) GaP/Si for High Performance InGaSb/GaSb Quantum Well Light-Emitting Diodes. ACS Appl Mater Interfaces 2023; 15:55965-55974. [PMID: 37978916 DOI: 10.1021/acsami.3c10979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Monolithic integration of GaSb-based optoelectronic devices on Si is a promising approach for achieving a low-cost, compact, and scalable infrared photonics platform. While tremendous efforts have been put into reducing dislocation densities by using various defect filter layers, exploring other types of extended crystal defects that can exist on GaSb/Si buffers has largely been neglected. Here, we show that GaSb growth on Si generates a high density of micro-twin (MT) defects as well as threading dislocations (TDs) to accommodate the extremely large misfit between GaSb and Si. We found that a 250 nm AlSb single insertion layer is more effective than AlSb/GaSb strained superlattices in reducing both types of defects, resulting in a 4× and 13× reduction in TD density and MT density, respectively, compared with a reference sample with no defect filter layer. InGaSb quantum well light-emitting diodes were grown on the GaSb/Si templates, and the effect of TD density and MT density on their performance was studied. This work shows the importance of using appropriate defect filter layers for high performance GaSb-based optoelectronic devices on standard on-axis (001) Si via direct epitaxial growth.
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Affiliation(s)
- Eungbeom Yeon
- Center for Optoelectronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea
- Department of Materials Science and Engineering, Korea University, Seoul 02481, South Korea
| | - Seungwan Woo
- Center for Optoelectronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, South Korea
| | - Rafael Jumar Chu
- Center for Optoelectronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea
- Division of Nanoscience and Technology, University of Science and Technology, Seoul 02792, South Korea
| | - In-Hwan Lee
- Department of Materials Science and Engineering, Korea University, Seoul 02481, South Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 08826, South Korea
| | - Daehwan Jung
- Center for Optoelectronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea
- Division of Nanoscience and Technology, University of Science and Technology, Seoul 02792, South Korea
| | - Won Jun Choi
- Center for Optoelectronic Materials and Devices, Korea Institute of Science and Technology, Seoul 02792, South Korea
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Saruta Y, Sugawara K, Oka H, Kawakami T, Kato T, Nakayama K, Souma S, Takahashi T, Fukumura T, Sato T. Moiré-Assisted Realization of Octahedral MoTe 2 Monolayer. Adv Sci (Weinh) 2023; 10:e2304461. [PMID: 37867224 DOI: 10.1002/advs.202304461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/24/2023] [Indexed: 10/24/2023]
Abstract
A current key challenge in 2D materials is the realization of emergent quantum phenomena in hetero structures via controlling the moiré potential created by the periodicity mismatch between adjacent layers, as highlighted by the discovery of superconductivity in twisted bilayer graphene. Generally, the lattice structure of the original host material remains unchanged even after the moiré superlattice is formed. However, much less attention is paid for the possibility that the moiré potential can also modify the original crystal structure itself. Here, it is demonstrated that octahedral MoTe2 which is unstable in bulk is stabilized in a commensurate MoTe2 /graphene hetero-bilayer due to the moiré potential created between the two layers. It is found that the reconstruction of electronic states via the moiré potential is responsible for this stabilization, as evidenced by the energy-gap opening at the Fermi level observed by angle-resolved photoemission and scanning tunneling spectroscopies. The present results provide a fresh approach to realize novel 2D quantum phases by utilizing the moiré potential.
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Affiliation(s)
- Yasuaki Saruta
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Katsuaki Sugawara
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Tokyo, 102-0076, Japan
| | - Hirofumi Oka
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
| | - Tappei Kawakami
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Takemi Kato
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Kosuke Nakayama
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Tokyo, 102-0076, Japan
| | - Seigo Souma
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
- Center for Science and Innovation in Spintronics (CSIS), Tohoku University, Sendai, 980-8577, Japan
| | - Takashi Takahashi
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Tomoteru Fukumura
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
| | - Takafumi Sato
- Department of Physics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan
- Center for Science and Innovation in Spintronics (CSIS), Tohoku University, Sendai, 980-8577, Japan
- International Center for Synchrotron Radiation Innovation Smart (SRIS), Tohoku University, Sendai, 980-8577, Japan
- Mathematical Science Center for Co-creative Society (MathCCS), Tohoku University, Sendai, 980-8578, Japan
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31
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Yu F, Qiu X, Zhou J, Huang L, Yang B, Liu J, Wu D, Wang G, Zhang Y. Tailoring the Structure and Properties of Epitaxial Europium Tellurides on Si(100) through Substrate Temperature Control. Materials (Basel) 2023; 16:7093. [PMID: 38005023 PMCID: PMC10672566 DOI: 10.3390/ma16227093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/31/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023]
Abstract
In this study, we improved the growth procedure of EuTe and realized the epitaxial growth of EuTe4. Our research demonstrated a selective growth of both EuTe and EuTe4 on Si(100) substrates using the molecular beam epitaxy (MBE) technique and reveals that the substrate temperature plays a crucial role in determining the structural phase of the grown films: EuTe can be obtained at a substrate temperature of 220 °C while lowering down the temperature to 205 °C leads to the formation of EuTe4. A comparative analysis of the transmittance spectra of these two films manifested that EuTe is a semiconductor, whereas EuTe4 exhibits charge density wave (CDW) behavior at room temperature. The magnetic measurements displayed the antiferromagnetic nature in EuTe and EuTe4, with Néel temperatures of 10.5 and 7.1 K, respectively. Our findings highlight the potential for controllable growth of EuTe and EuTe4 thin films, providing a platform for further exploration of magnetism and CDW phenomena in rare earth tellurides.
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Affiliation(s)
- Fan Yu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
| | - Xiaodong Qiu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
| | - Jinming Zhou
- Department of Physics, and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lin Huang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
| | - Bin Yang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
| | - Junming Liu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Di Wu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Gan Wang
- Department of Physics, and Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Shenzhen 518055, China
| | - Yi Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing 210093, China; (F.Y.)
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Hefei National Laboratory, Hefei 230088, China
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32
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Ji J, Zhou Y, Zhou B, Desgué E, Legagneux P, Jepsen PU, Bøggild P. Probing Carrier Dynamics in Large-Scale MBE-Grown PtSe 2 Films by Terahertz Spectroscopy. ACS Appl Mater Interfaces 2023. [PMID: 37883033 DOI: 10.1021/acsami.3c09792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Atomically thin platinum diselenide (PtSe2) films are promising for applications in the fields of electronics, spintronics, and photodetectors owing to their tunable electronic structure and high carrier mobility. Using terahertz (THz) spectroscopy techniques, we investigated the layer-dependent semiconducting-to-metallic phase transition and associated intrinsic carrier dynamics in large-scale PtSe2 films grown by molecular beam epitaxy. The uniformity of large-scale PtSe2 films was characterized by spatially and frequency-resolved THz-based sheet conductivity mapping. Furthermore, we use an optical-pump-THz-probe technique to study the transport dynamics of photoexcited carriers and explore light-induced intergrain carrier transport in PtSe2 films. We demonstrate large-scale THz-based mapping of the electrical properties of transition metal dichalcogenide films and show that the two noncontact THz-based approaches provide insight in the spatial and temporal properties of PtSe2 films.
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Affiliation(s)
- Jie Ji
- Department of Physics, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Yingqiu Zhou
- Department of Physics, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Binbin Zhou
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Eva Desgué
- Thales Research and Technology, Palaiseau 91767, France
| | | | - Peter Uhd Jepsen
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Peter Bøggild
- Department of Physics, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
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33
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Koussir H, Chernukha Y, Sthioul C, Haber E, Peric N, Biadala L, Capiod P, Berthe M, Lefebvre I, Wallart X, Grandidier B, Diener P. Large-Area Epitaxial Mott Insulating 1T-TaSe 2 Monolayer on GaP(111)B. Nano Lett 2023; 23:9413-9419. [PMID: 37820373 DOI: 10.1021/acs.nanolett.3c02813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Two-dimensional Mott materials have recently been reported in the dichalcogenide family with high potential for Mottronic applications. Nevertheless, their widespread use as a single or few layers is hampered by their limited device integration resulting from their growth on graphene, a metallic substrate. Here, we report on the fabrication of 1T-TaSe2 monolayers grown by molecular beam epitaxy on semiconducting gallium phosphide substrates. At the nanoscale, the charge density wave reconstruction and a moiré pattern resulting from the monolayer interaction with the substrate are observed by scanning tunneling microscopy. The fully open gap unveiled by tunneling spectroscopy, which can be further manipulated by the proximity of a metal tip, is confirmed by transport measurements from micrometric to millimetric scales, demonstrating a robust Mott insulating phase at up to 400 K.
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Affiliation(s)
- H Koussir
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Y Chernukha
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - C Sthioul
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - E Haber
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - N Peric
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - L Biadala
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Capiod
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - M Berthe
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - I Lefebvre
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - X Wallart
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - B Grandidier
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Diener
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
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34
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Pathirage V, Khatun S, Lisenkov S, Lasek K, Li J, Kolekar S, Valvidares M, Gargiani P, Xin Y, Ponomareva I, Batzill M. 2D Materials by Design: Intercalation of Cr or Mn between two VSe 2 van der Waals Layers. Nano Lett 2023; 23:9579-9586. [PMID: 37818868 DOI: 10.1021/acs.nanolett.3c03169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Insertion of metal layers between layered transition-metal dichalcogenides (TMDs) enables the design of new pseudo-2D nanomaterials. The general premise is that various metal atoms may adopt energetically favorable intercalation sites between two TMD sheets. These covalently bound metals arrange in metastable configurations and thus enable the controlled synthesis of nanomaterials in a bottom-up approach. Here, this method is demonstrated by the insertion of Cr or Mn between VSe2 layers. Vacuum-deposited transition metals diffuse between VSe2 layers with increasing concentration, arranging in ordered phases. The Cr3+ or Mn2+ ions are in octahedral coordination and thus in a high-spin state. Measured and computed magnetic moments are high for dilute Cr atoms, but with increasing Cr concentration the average magnetic moment decreases, suggesting antiferromagnetic ordering between Cr ions. The many possible combinations of transition metals with TMDs form a library for exploring quantum phenomena in these nanomaterials.
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Affiliation(s)
- Vimukthi Pathirage
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Salma Khatun
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Sergey Lisenkov
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Kinga Lasek
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Jingfeng Li
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Sadhu Kolekar
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Manuel Valvidares
- ALBA Synchrotron Light Source E-08290 Cerdanyola del Vallès, Barcelona, Spain
| | - Pierluigi Gargiani
- ALBA Synchrotron Light Source E-08290 Cerdanyola del Vallès, Barcelona, Spain
| | - Yan Xin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 United States
| | - Inna Ponomareva
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
| | - Matthias Batzill
- Department of Physics, University of South Florida, Tampa, Florida 33647, United States
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Olszewski K, Sobanska M, Dubrovskii VG, Leshchenko ED, Wierzbicka A, Zytkiewicz ZR. Geometrical Selection of GaN Nanowires Grown by Plasma-Assisted MBE on Polycrystalline ZrN Layers. Nanomaterials (Basel) 2023; 13:2587. [PMID: 37764616 PMCID: PMC10537475 DOI: 10.3390/nano13182587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
GaN nanowires grown on metal substrates have attracted increasing interest for a wide range of applications. Herein, we report GaN nanowires grown by plasma-assisted molecular beam epitaxy on thin polycrystalline ZrN buffer layers, sputtered onto Si(111) substrates. The nanowire orientation was studied by X-ray diffraction and scanning electron microscopy, and then described within a model as a function of the Ga beam angle, nanowire tilt angle, and substrate rotation. We show that vertically aligned nanowires grow faster than inclined nanowires, which leads to an interesting effect of geometrical selection of the nanowire orientation in the directional molecular beam epitaxy technique. After a given growth time, this effect depends on the nanowire surface density. At low density, the nanowires continue to grow with random orientations as nucleated. At high density, the effect of preferential growth induced by the unidirectional supply of the material in MBE starts to dominate. Faster growing nanowires with smaller tilt angles shadow more inclined nanowires that grow slower. This helps to obtain more regular ensembles of vertically oriented GaN nanowires despite their random position induced by the metallic grains at nucleation. The obtained dense ensembles of vertically aligned GaN nanowires on ZrN/Si(111) surfaces are highly relevant for device applications. Importantly, our results are not specific for GaN nanowires on ZrN buffers, and should be relevant for any nanowires that are epitaxially linked to the randomly oriented surface grains in the directional molecular beam epitaxy.
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Affiliation(s)
- Karol Olszewski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Marta Sobanska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Vladimir G. Dubrovskii
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13V, 199034 St. Petersburg, Russia; (V.G.D.)
| | - Egor D. Leshchenko
- Faculty of Physics, St. Petersburg State University, Universitetskaya Embankment 13V, 199034 St. Petersburg, Russia; (V.G.D.)
| | - Aleksandra Wierzbicka
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
| | - Zbigniew R. Zytkiewicz
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland (Z.R.Z.)
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36
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Concordel A, Rochat N, Quach AMN, Rouvière JL, Jacopin G, Napierala J, Daudin B. Inhomogeneous spatial distribution of non radiative recombination centers in GaN/InGaN nanowire heterostructures studied by cathodoluminescence. Nanotechnology 2023; 34:495702. [PMID: 37640021 DOI: 10.1088/1361-6528/acf473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/27/2023] [Indexed: 08/31/2023]
Abstract
In order to elucidate the mechanisms responsible for cathodoluminescence intensity variations at the scale of single InGaN/GaN nanowire heterostructures, a methodology is proposed based on a statistical analysis on ensembles of several hundreds of nanowires exhibiting a diameter of 180, 240 and 280 nm. For 180 nm diameter, we find that intensitiy variations are consistent with incorporation of point defects obeying Poisson's statistics. For wider diameters, intensity variations at the scale of single NWs are observed and assigned to local growth conditions fluctuations. Finally, for the less luminescent nanowires, a departure from Poisson's statistics is observed suggesting the possible clustering of non independent point defects.
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Affiliation(s)
- Alexandre Concordel
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, NPSC, 17 av. des Martyrs, 38000 Grenoble, France
| | - Névine Rochat
- Univ. Grenoble Alpes, CEA, LETI, 17 rue des martyrs, 38000 Grenoble, France
| | - Anh My Naht Quach
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, NPSC, 17 av. des Martyrs, 38000 Grenoble, France
| | - Jean-Luc Rouvière
- Univ. Grenoble Alpes, Grenoble INP, CEA, IRIG-MEM, LEMMA, 17 rue des martyrs, 38000 Grenoble, France
| | - Gwénolé Jacopin
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | | | - Bruno Daudin
- Univ. Grenoble Alpes, CEA, Grenoble INP, IRIG, PHELIQS, NPSC, 17 av. des Martyrs, 38000 Grenoble, France
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37
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van Treeck D, Lähnemann J, Brandt O, Geelhaar L. Growth mechanisms in molecular beam epitaxy for GaN-(In,Ga)N core-shell nanowires emitting in the green spectral range. Nanotechnology 2023; 34. [PMID: 37625397 DOI: 10.1088/1361-6528/acf3f5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 08/24/2023] [Indexed: 08/27/2023]
Abstract
Using molecular beam epitaxy, we demonstrate the growth of (In,Ga)N shells emitting in the green spectral range around very thin (35 nm diameter) GaN core nanowires. These GaN nanowires are obtained by self-assembled growth on TiN. We present a qualitative shell growth model accounting for both the three-dimensional nature of the nanostructures as well as the directionality of the atomic fluxes. This model allows us, on the one hand, to optimise the conditions for high and homogeneous In incorporation and, on the other hand, to explain the influence of changes in the growth conditions on the sample morphology and In content. Specifically, the impact of the V/III and In/Ga flux ratios, the rotation speed and the rotation direction are investigated. Notably, with In acting as surfactant, the ternary (In,Ga)N shells are much more homogeneous in thickness along the nanowire length than their binary GaN counterparts.
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Affiliation(s)
- David van Treeck
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - Jonas Lähnemann
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - Oliver Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - Lutz Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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38
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Nie JH, Xie T, Chen G, Zhang W, Fu YS. Moiré Enhanced Two-Band Superconductivity in a MnTe/NbSe 2 Heterojunction. Nano Lett 2023; 23:8370-8377. [PMID: 37656911 DOI: 10.1021/acs.nanolett.3c02772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Recent advances in creating moiré periods of two-dimensional heterostructures enable diverse and compatible tunability to modulate the conventional proximity effect involving superconductivity, magnetism, and topology. Here, by constructing a MnTe/NbSe2 heterojunction via molecular beam epitaxy growth, we report on a moiré-enhanced multiband superconductivity by low-temperature scanning tunneling microscopy/spectroscopy measurements. We observe a distinct double-gap superconducting spectrum on monolayer MnTe that is absent on the NbSe2 substrate. The subgap character exhibits a moiré-related oscillation in real space, which can be well described by an effective two-band model. The restored two-gap feature and its rapid suppression under a small magnetic field are speculated to be mediated by the moiré superlattice, which is closely related to the enhanced interband coupling strength of quasiparticle scattering. Our work paves the way for engineering proximitized properties of heterostructures by a moiré landscape with spatial modulations.
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Affiliation(s)
- Jin-Hua Nie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Tao Xie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Gang Chen
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
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Moon J, Zou Q, Zhang H, van 't Erve OMJ, Combs NG, Li L, Li CH. Magnetic Field-Induced Spin Nematic Phase Up to Room Temperature in Epitaxial Antiferromagnetic FeTe Thin Films Grown by Molecular Beam Epitaxy. ACS Nano 2023; 17:16886-16894. [PMID: 37595094 DOI: 10.1021/acsnano.3c03880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
Electronic nematicity, where strong correlations drive electrons to align in a way that lowers the crystal symmetry, is ubiquitous among unconventional superconductors. Understanding the interplay of such a nematic state with other electronic phases underpins the complex behavior of these materials and the potential for tuning their properties through external stimuli. Here, we report magnetic field-induced spin nematicity in a model system tetragonal FeTe, the parent compound of iron chalcogenide superconductors, which exhibits a bicollinear antiferromagnetic order. The studies were conducted on epitaxial FeTe thin films grown on SrTiO3(001) substrates by molecular beam epitaxy, where the bicollinear antiferromagnetic order was confirmed by in situ atomic resolution scanning tunneling microscopy imaging. A 2-fold anisotropy is observed in in-plane angle-dependent magnetoresistance measurements, indicative of magnetic field-induced nematicity. Such 2-fold anisotropy persists up to 300 K, well-above the bicollinear antiferromagnetic ordering temperature of 75 K, indicating a magnetic field-induced spin nematic phase up to room temperature in the antiferromagnet FeTe.
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Affiliation(s)
- Jisoo Moon
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Qiang Zou
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Huimin Zhang
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Olaf M J van 't Erve
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Nicholas G Combs
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
| | - Lian Li
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375, United States
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Wang J, Bagheri Tagani M, Zhang L, Xia Y, Wu Q, Li B, Tian Y, Yin LJ, Zhang L, Qin Z. Realization of black phosphorus-like PbSe monolayer on Au(111) via epitaxial growth. J Phys Condens Matter 2023; 35:485002. [PMID: 37586387 DOI: 10.1088/1361-648x/acf107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/16/2023] [Indexed: 08/18/2023]
Abstract
Lead selenide (PbSe) has been attracted a lot attention in fundamental research and industrial applications due to its excellent infrared optical and thermoelectric properties, toward reaching the two-dimensional limit. Herein, we realize the black phosphorus-like PbSe (α-phase PbSe) monolayer on Au(111) via epitaxial growth, where a characteristic rectangular superlattice of 5 Å × 9 Å corresponding to 1 × 2 reconstruction with respect to the pristine ofα-phase PbSe is observed by scanning tunneling microscopy. Corresponding density functional theory calculation confirmed the reconstruction and revealed the driven mechanism, the coupling between monolayer PbSe and Au(111) substrate. The metallic feature of differential conductance spectra as well as the transition of the density of states from semiconductor to metal further verified such coupling. As the unique anisotropic structure, our study provides a pathway towards the synthesis of BP-PbSe monolayer. In addition, it builds up an ideal platform for studying fundamental physics and also excellent prospects in PbSe-based device applications.
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Affiliation(s)
- Jing Wang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | | | - Li Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Yu Xia
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Qilong Wu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Bo Li
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Yuan Tian
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Long-Jing Yin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Lijie Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Zhihui Qin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
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John P, Gómez Ruiz M, van Deurzen L, Lähnemann J, Trampert A, Geelhaar L, Brandt O, Auzelle T. Growth kinetics and substrate stability during high-temperature molecular beam epitaxy of AlN nanowires. Nanotechnology 2023; 34. [PMID: 37579739 DOI: 10.1088/1361-6528/acefd8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/13/2023] [Indexed: 08/16/2023]
Abstract
We study the molecular beam epitaxy of AlN nanowires between 950 °C and 1215 °C, well above the usual growth temperatures, to identify optimal growth conditions. The nanowires are grown by self-assembly on TiN(111) films sputtered onto Al2O3. Above 1100 °C, the TiN film is seen to undergo grain growth and its surface exhibits {111} facets where AlN nucleation preferentially occurs. Modeling of the nanowire elongation rate measured at different temperatures shows that the Al adatom diffusion length maximizes at 1150 °C, which appears to be the optimum growth temperature. However, analysis of the nanowire luminescence shows a steep increase in the deep-level signal already above 1050 °C, associated with O incorporation from the Al2O3substrate. Comparison with AlN nanowires grown on Si, MgO and SiC substrates suggests that heavy doping of Si and O by interdiffusion from the TiN/substrate interface increases the nanowire internal quantum efficiency, presumably due to the formation of a SiNxor AlOxpassivation shell. The outdiffusion of Si and O would also cause the formation of the inversion domains observed in the nanowires. It follows that for optoelectronic and piezoelectric applications, optimal AlN nanowire ensembles should be prepared at 1150 °C on TiN/SiC substrates and will require anex situsurface passivation.
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Affiliation(s)
- P John
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - M Gómez Ruiz
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L van Deurzen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, United States of America
| | - J Lähnemann
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - A Trampert
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - L Geelhaar
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - O Brandt
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
| | - T Auzelle
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, D-10117 Berlin, Germany
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Shandyba N, Kirichenko D, Sharov V, Chernenko N, Balakirev S, Solodovnik M. Modulation of GaAs nanowire growth by pre-treatment of Si substrate using a Ga focused ion beam. Nanotechnology 2023; 34:465603. [PMID: 37557087 DOI: 10.1088/1361-6528/acee84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/08/2023] [Indexed: 08/11/2023]
Abstract
We reveal a novel phenomenon observed after self-catalytic growth of GaAs nanowires (NWs) on Si(111) substrates treated with a Ga focused ion beam (FIB). Depending on the ion dose, NW arrays with various geometrical parameters can be obtained. A minor treatment of the substrate enables a slight increase in the surface density of NWs relative to an unmodified substrate area. As the ion dose is increased up to ∼0.1 pCμm-2, the growth of GaAs NWs and nanocrystals is suppressed. However, a further increase in the ion dose stimulates the crystal growth leading to the formation of extremely thin NWs (39 ± 5 nm) with a remarkably high surface density of up to 15μm-2. Resting upon an analysis of the surface structure before and after stages of ion-beam treatment, ultra-high vacuum annealing and NW growth, we propose a mechanism underlying the phenomenon observed. We assume that the chemical interaction between embedded Ga ions and a native Si oxide layer leads either to the enhancement of the passivation properties of the oxide layer within FIB-modified areas (at low and middle ion doses), or to the etching of the passivating oxide layer by excess Ga atoms, resulting in the formation of pores (at high ion doses). Due to this behavior, local fabrication of GaAs NW arrays with a diverse range of characteristics can be implemented on the same substrate. This approach opens a new way for self-catalytic growth of GaAs NWs.
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Affiliation(s)
- Nikita Shandyba
- Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia
| | - Danil Kirichenko
- Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia
| | - Vladislav Sharov
- Laboratory of Renewable Energy Sources, Alferov University, Saint Petersburg 194021, Russia
- Laboratory of Surface Optics, Ioffe Institute, Saint Petersburg 194021, Russia
| | - Natalia Chernenko
- Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia
| | - Sergey Balakirev
- Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia
| | - Maxim Solodovnik
- Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia
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Zaiter A, Nikitskiy N, Nemoz M, Vuong P, Ottapilakkal V, Sundaram S, Ougazzaden A, Brault J. (Al, Ga)N-Based Quantum Dots Heterostructures on h-BN for UV-C Emission. Nanomaterials (Basel) 2023; 13:2404. [PMID: 37686912 PMCID: PMC10489961 DOI: 10.3390/nano13172404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/27/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
Aluminium Gallium Nitride (AlyGa1-yN) quantum dots (QDs) with thin sub-µm AlxGa1-xN layers (with x > y) were grown by molecular beam epitaxy on 3 nm and 6 nm thick hexagonal boron nitride (h-BN) initially deposited on c-sapphire substrates. An AlN layer was grown on h-BN and the surface roughness was investigated by atomic force microscopy for different deposited thicknesses. It was shown that for thicker AlN layers (i.e., 200 nm), the surface roughness can be reduced and hence a better surface morphology is obtained. Next, AlyGa1-yN QDs embedded in Al0.7Ga0.3N cladding layers were grown on the AlN and investigated by atomic force microscopy. Furthermore, X-ray diffraction measurements were conducted to assess the crystalline quality of the AlGaN/AlN layers and examine the impact of h-BN on the subsequent layers. Next, the QDs emission properties were studied by photoluminescence and an emission in the deep ultra-violet, i.e., in the 275-280 nm range was obtained at room temperature. Finally, temperature-dependent photoluminescence was performed. A limited decrease in the emission intensity of the QDs with increasing temperatures was observed as a result of the three-dimensional confinement of carriers in the QDs.
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Affiliation(s)
- Aly Zaiter
- Université Côte d’Azur, Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur l’Hétéro-Epitaxie et ses Applications (CRHEA), 06560 Valbonne, France;
| | - Nikita Nikitskiy
- Université Côte d’Azur, Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur l’Hétéro-Epitaxie et ses Applications (CRHEA), 06560 Valbonne, France;
| | - Maud Nemoz
- Université Côte d’Azur, Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur l’Hétéro-Epitaxie et ses Applications (CRHEA), 06560 Valbonne, France;
| | - Phuong Vuong
- CNRS, IRL 2958 Georgia Tech-CNRS, 2 rue Marconi, 57070 Metz, France; (P.V.); (V.O.); (S.S.); (A.O.)
- Georgia Tech-Europe, 2 rue Marconi, 57070 Metz, France
| | - Vishnu Ottapilakkal
- CNRS, IRL 2958 Georgia Tech-CNRS, 2 rue Marconi, 57070 Metz, France; (P.V.); (V.O.); (S.S.); (A.O.)
| | - Suresh Sundaram
- CNRS, IRL 2958 Georgia Tech-CNRS, 2 rue Marconi, 57070 Metz, France; (P.V.); (V.O.); (S.S.); (A.O.)
- Georgia Tech-Europe, 2 rue Marconi, 57070 Metz, France
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, GA 30332-0250, USA
| | - Abdallah Ougazzaden
- CNRS, IRL 2958 Georgia Tech-CNRS, 2 rue Marconi, 57070 Metz, France; (P.V.); (V.O.); (S.S.); (A.O.)
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, GA 30332-0250, USA
| | - Julien Brault
- Université Côte d’Azur, Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur l’Hétéro-Epitaxie et ses Applications (CRHEA), 06560 Valbonne, France;
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Zscherp MF, Jentsch SA, Müller MJ, Lider V, Becker C, Chen L, Littmann M, Meier F, Beyer A, Hofmann DM, As DJ, Klar PJ, Volz K, Chatterjee S, Schörmann J. Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic In xGa 1-xN. ACS Appl Mater Interfaces 2023; 15:39513-39522. [PMID: 37530411 DOI: 10.1021/acsami.3c06319] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The lack of internal polarization fields in cubic group-III nitrides makes them promising arsenic-free contenders for next-generation high-performance electronic and optoelectronic applications. In particular, cubic InxGa1-xN semiconductor alloys promise band gap tuning across and beyond the visible spectrum, from the near-ultraviolet to the near-infrared. However, realization across the complete composition range has been deemed impossible due to a miscibility gap corresponding to the amber spectral range. In this study, we use plasma-assisted molecular beam epitaxy (PAMBE) to fabricate cubic InxGa1-xN films on c-GaN/AlN/3C-SiC/Si template substrates that overcome this challenge by careful adjustment of the growth conditions, conclusively closing the miscibility gap. X-ray diffraction reveals the composition, phase purity, and strain properties of the InxGa1-xN films. Scanning transmission electron microscopy reveals a CuPt-type ordering on the atomistic scale in highly alloyed films with x(In) ≈ 0.5. Layers with much lower and much higher indium content exhibit statistical distributions of the cations Ga and In. Notably, this CuPt-type ordering results in a spectrally narrower emission compared to that of statistically disordered zincblende materials. The emission energies of the films range from 3.24 to 0.69 eV and feature a quadratic bowing parameter of b = 2.4 eV. In contrast, the LO-like phonon modes that are observed by Raman spectroscopy exhibit a one-mode behavior and shift linearly from c-GaN to c-InN.
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Affiliation(s)
- Mario Fabian Zscherp
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Silas Aurel Jentsch
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Marius Johannes Müller
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Vitalii Lider
- Materials Science Center and Faculty of Physics, Philipps-University Marburg, Hans-Meerwein-Strasse 6, D-35032 Marburg, Germany
| | - Celina Becker
- Materials Science Center and Faculty of Physics, Philipps-University Marburg, Hans-Meerwein-Strasse 6, D-35032 Marburg, Germany
| | - Limei Chen
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Mario Littmann
- Department of Physics, Paderborn University, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - Falco Meier
- Department of Physics, Paderborn University, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - Andreas Beyer
- Materials Science Center and Faculty of Physics, Philipps-University Marburg, Hans-Meerwein-Strasse 6, D-35032 Marburg, Germany
| | - Detlev Michael Hofmann
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Donat Josef As
- Department of Physics, Paderborn University, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - Peter Jens Klar
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Kerstin Volz
- Materials Science Center and Faculty of Physics, Philipps-University Marburg, Hans-Meerwein-Strasse 6, D-35032 Marburg, Germany
| | - Sangam Chatterjee
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
| | - Jörg Schörmann
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany
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Brahlek M, Mazza AR, Annaberdiyev A, Chilcote M, Rimal G, Halász GB, Pham A, Pai YY, Krogel JT, Lapano J, Lawrie BJ, Eres G, McChesney J, Prokscha T, Suter A, Oh S, Freeland JW, Cao Y, Gardner JS, Salman Z, Moore RG, Ganesh P, Ward TZ. Emergent Magnetism with Continuous Control in the Ultrahigh-Conductivity Layered Oxide PdCoO 2. Nano Lett 2023; 23:7279-7287. [PMID: 37527431 DOI: 10.1021/acs.nanolett.3c01065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The current challenge to realizing continuously tunable magnetism lies in our inability to systematically change properties, such as valence, spin, and orbital degrees of freedom, as well as crystallographic geometry. Here, we demonstrate that ferromagnetism can be externally turned on with the application of low-energy helium implantation and can be subsequently erased and returned to the pristine state via annealing. This high level of continuous control is made possible by targeting magnetic metastability in the ultrahigh-conductivity, nonmagnetic layered oxide PdCoO2 where local lattice distortions generated by helium implantation induce the emergence of a net moment on the surrounding transition metal octahedral sites. These highly localized moments communicate through the itinerant metal states, which trigger the onset of percolated long-range ferromagnetism. The ability to continuously tune competing interactions enables tailoring precise magnetic and magnetotransport responses in an ultrahigh-conductivity film and will be critical to applications across spintronics.
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Affiliation(s)
- Matthew Brahlek
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alessandro R Mazza
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Abdulgani Annaberdiyev
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael Chilcote
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gaurab Rimal
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Gábor B Halász
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Anh Pham
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yun-Yi Pai
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jaron T Krogel
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jason Lapano
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin J Lawrie
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Gyula Eres
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jessica McChesney
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Thomas Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Andreas Suter
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Seongshik Oh
- Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Yue Cao
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jason S Gardner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Zaher Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Robert G Moore
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - T Zac Ward
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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46
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Iimori T, Miyamachi T, Kajiwara T, Mase K, Tanaka S, Komori F, Nakatsuji K. Width-dependent band gap of arm-chair graphene nanoribbons formed on vicinal SiC substrates by MBE. J Phys Condens Matter 2023; 35:455002. [PMID: 37536324 DOI: 10.1088/1361-648x/aced30] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/03/2023] [Indexed: 08/05/2023]
Abstract
Formation and electronic states of graphene nanoribbons with arm-chair edges (AGNR) are studied on the SiC(0001) vicinal surfaces toward the [11-00] direction. The surface step and terrace structures of both 4H and 6H-SiC substrates are used as the growth templates of one-dimensional arrays of AGNRs, which are prepared using the carbon molecular beam epitaxy followed by hydrogen intercalation. A band gap is observed above theπ-band maximum by angle-resolved photoelectron spectroscopy (ARPES) for the both samples. The average widths of the AGNRs are 6 and 10 nm, and the estimated average band gaps are 0.40 and 0.28 eV for the 4H- and 6H- substrates, respectively. A simple and phenomenological inverse relation between the energy gap and AGNR width works in the analyses of the ARPES data.
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Affiliation(s)
- Takushi Iimori
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Toshio Miyamachi
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Takashi Kajiwara
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Kazuhiko Mase
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
- Department of Materials Structure Science, SOKENDAI (The Graduate University for Advanced Studies), Tsukuba, Ibaraki 305-0801, Japan
| | - Satoru Tanaka
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Fumio Komori
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502, Japan
| | - Kan Nakatsuji
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502, Japan
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47
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Cheng S, Nrisimhamurty M, Zhou T, Bagués N, Zhou W, Bishop AJ, Lyalin I, Jozwiak C, Bostwick A, Rotenberg E, McComb DW, Žutić I, Kawakami RK. Epitaxial Kagome Thin Films as a Platform for Topological Flat Bands. Nano Lett 2023; 23:7107-7113. [PMID: 37506350 DOI: 10.1021/acs.nanolett.3c01961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Systems with flat bands are ideal for studying strongly correlated electronic states and related phenomena. Among them, kagome-structured metals such as CoSn have been recognized as promising candidates due to the proximity between the flat bands and the Fermi level. A key next step will be to realize epitaxial kagome thin films with flat bands to enable tuning of the flat bands across the Fermi level via electrostatic gating or strain. Here, we report the band structures of epitaxial CoSn thin films grown directly on the insulating substrates. Flat bands are observed by using synchrotron-based angle-resolved photoemission spectroscopy (ARPES). The band structure is consistent with density functional theory (DFT) calculations, and the transport properties are quantitatively explained by the band structure and semiclassical transport theory. Our work paves the way to realize flat band-induced phenomena through fine-tuning of flat bands in kagome materials.
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Affiliation(s)
- Shuyu Cheng
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - M Nrisimhamurty
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Tong Zhou
- Department of Physics, University at Buffalo, Buffalo, New York 14260, United States
| | - Núria Bagués
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wenyi Zhou
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Alexander J Bishop
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Igor Lyalin
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chris Jozwiak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Aaron Bostwick
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eli Rotenberg
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - David W McComb
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210, United States
| | - Igor Žutić
- Department of Physics, University at Buffalo, Buffalo, New York 14260, United States
| | - Roland K Kawakami
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
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48
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Sun W, Li Y, Liu R, Yang J, Li J, Wei W, Jin G, Yan S, Sun H, Guo W, Gu Z, Zhu Z, Sun Y, Shi Z, Deng Y, Wang X, Nie Y. Evidence for Anisotropic Superconductivity Beyond Pauli Limit in Infinite-Layer Lanthanum Nickelates. Adv Mater 2023; 35:e2303400. [PMID: 37235743 DOI: 10.1002/adma.202303400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/14/2023] [Indexed: 05/28/2023]
Abstract
After being expected to be a promising analog to cuprates for decades, superconductivity has recently been discovered in infinite-layer nickelates, providing new opportunities to explore mechanisms of high-temperature superconductivity. However, in sharp contrast to the single-band and anisotropic superconductivity in cuprates, nickelates exhibit a multi-band electronic structure and an unexpected isotropic superconductivity as reported recently, which challenges the cuprate-like picture in nickelates. Here, it is shown that strong anisotropic magnetotransport behaviors exist in La-based nickelate films with enhanced crystallinity and superconductivity (T c onset $T_{\rm{c}}^{{\rm{onset}}}$ = 18.8 K,T c zero $T_{\rm{c}}^{{\rm{zero}}}$ = 16.5 K). The upper critical fields are anisotropic and violate the estimated Bardeen-Cooper-Schrieffer (BCS) Pauli limit (H Pauli , μ = 1 μ B = 1.86 × T c , H = 0 ${H}_{\mathrm{Pauli},\mu =1{\mu}_{B}}=1.86\ensuremath{\times{}}{T}_{\mathrm{c},H=0}$ ) for in-plane magnetic fields. Moreover, the anisotropic superconductivity is further manifested by the cusp-like peak of the angle-dependent Tc and the vortex motion anisotropy under external magnetic fields.
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Affiliation(s)
- Wenjie Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Yueying Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Ruxin Liu
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Jiangfeng Yang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Jiayi Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Wei Wei
- Department of Physics, Southeast University, Nanjing, 211189, P. R. China
| | - Gangjian Jin
- School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Shengjun Yan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Haoying Sun
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Wei Guo
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Zhengbin Gu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Zengwei Zhu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yue Sun
- Department of Physics, Southeast University, Nanjing, 211189, P. R. China
| | - Zhixiang Shi
- Department of Physics, Southeast University, Nanjing, 211189, P. R. China
| | - Yu Deng
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Xuefeng Wang
- Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Yuefeng Nie
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
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49
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Jalil AR, Hou X, Schüffelgen P, Bae JH, Neumann E, Mussler G, Plucinski L, Grützmacher D. Phase-Selective Epitaxy of Trigonal and Orthorhombic Bismuth Thin Films on Si (111). Nanomaterials (Basel) 2023; 13:2143. [PMID: 37513154 PMCID: PMC10386495 DOI: 10.3390/nano13142143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/16/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023]
Abstract
Over the past three decades, the growth of Bi thin films has been extensively explored due to their potential applications in various fields such as thermoelectrics, ferroelectrics, and recently for topological and neuromorphic applications, too. Despite significant research efforts in these areas, achieving reliable and controllable growth of high-quality Bi thin-film allotropes has remained a challenge. Previous studies have reported the growth of trigonal and orthorhombic phases on various substrates yielding low-quality epilayers characterized by surface morphology. In this study, we present a systematic growth investigation, enabling the high-quality growth of Bi epilayers on Bi-terminated Si (111) 1 × 1 surfaces using molecular beam epitaxy. Our work yields a phase map that demonstrates the realization of trigonal, orthorhombic, and pseudocubic thin-film allotropes of Bi. In-depth characterization through X-ray diffraction (XRD) techniques and scanning transmission electron microscopy (STEM) analysis provides a comprehensive understanding of phase segregation, phase stability, phase transformation, and phase-dependent thickness limitations in various Bi thin-film allotropes. Our study provides recipes for the realization of high-quality Bi thin films with desired phases, offering opportunities for the scalable refinement of Bi into quantum and neuromorphic devices and for revisiting technological proposals for this versatile material platform from the past 30 years.
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Affiliation(s)
- Abdur Rehman Jalil
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Peter Grünberg Institute (PGI-10), JARA-Green IT, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Xiao Hou
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Peter Schüffelgen
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Jin Hee Bae
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Elmar Neumann
- Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Gregor Mussler
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Lukasz Plucinski
- Peter Grünberg Institute (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Detlev Grützmacher
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT (Fundamentals of Future Information Technology), Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
- Peter Grünberg Institute (PGI-10), JARA-Green IT, Forschungszentrum Jülich, 52425 Jülich, Germany
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50
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Xiao R, Islam S, Yanez W, Ou Y, Liu H, Xie X, Chamorro J, McQueen TM, Samarth N. Influence of Magnetic and Electric Fields on Universal Conductance Fluctuations in Thin Films of the Dirac Semimetal Cd 3As 2. Nano Lett 2023. [PMID: 37318449 DOI: 10.1021/acs.nanolett.3c01174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Time-reversal invariance (TRS) and inversion symmetry (IS) are responsible for the topological band structure in Dirac semimetals (DSMs). These symmetries can be broken by applying an external magnetic or electric field, resulting in fundamental changes to the ground state Hamiltonian and a topological phase transition. We probe these changes using universal conductance fluctuations (UCF) in the prototypical DSM, Cd3As2. With increasing magnetic field, the magnitude of the UCF decreases by a factor of 2, in agreement with numerical calculations of the effect of broken TRS. In contrast, the magnitude of the UCF increases monotonically when the chemical potential is gated away from the charge neutrality point. We attribute this to Fermi surface anisotropy rather than broken IS. The concurrence between experimental data and theory provides unequivocal evidence that UCF are the dominant source of fluctuations and offers a general methodology for probing broken-symmetry effects in topological quantum materials.
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Affiliation(s)
- Run Xiao
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Saurav Islam
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Wilson Yanez
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yongxi Ou
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Haiwen Liu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Xincheng Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Hefei National Laboratory, Hefei 230088, People's Republic of China
| | - Juan Chamorro
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Tyrel M McQueen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Nitin Samarth
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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