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Maßmeyer O, Günkel R, Glowatzki J, Klement P, Ojaghi Dogahe B, Kachel SR, Gruber F, Müller M, Fey M, Schörmann J, Belz J, Beyer A, Gottfried JM, Chatterjee S, Volz K. Synthesis of 2D Gallium Sulfide with Ultraviolet Emission by MOCVD. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402155. [PMID: 38795001 DOI: 10.1002/smll.202402155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/18/2024] [Indexed: 05/27/2024]
Abstract
Two-dimensional (2D) materials exhibit the potential to transform semiconductor technology. Their rich compositional and stacking varieties allow tailoring materials' properties toward device applications. Monolayer to multilayer gallium sulfide (GaS) with its ultraviolet band gap, which can be tuned by varying the layer number, holds promise for solar-blind photodiodes and light-emitting diodes as applications. However, achieving commercial viability requires wafer-scale integration, contrasting with established, limited methods such as mechanical exfoliation. Here the one-step synthesis of 2D GaS is introduced via metal-organic chemical vapor deposition on sapphire substrates. The pulsed-mode deposition of industry-standard precursors promotes 2D growth by inhibiting the vapor phase and on-surface pre-reactions. The interface chemistry with the growth of a Ga adlayer that results in an epitaxial relationship is revealed. Probing structure and composition validate thin-film quality and 2D nature with the possibility to control the thickness by the number of GaS pulses. The results highlight the adaptability of established growth facilities for producing atomically thin to multilayered 2D semiconductor materials, paving the way for practical applications.
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Affiliation(s)
- Oliver Maßmeyer
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Robin Günkel
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Johannes Glowatzki
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Philip Klement
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392, Giessen, Germany
| | - Badrosadat Ojaghi Dogahe
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Stefan Renato Kachel
- Material Sciences Center and Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, Marburg, Germany
| | - Felix Gruber
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Marius Müller
- Institute of Experimental Physics I and Center for Materials Research, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392, Giessen, Germany
| | - Melanie Fey
- 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
| | - Jürgen Belz
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - Andreas Beyer
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
| | - J Michael Gottfried
- Material Sciences Center and Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35043, 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
| | - Kerstin Volz
- Material Sciences Center and Department of Physics, Philipps-Universität Marburg, Hans-Meerwein-Straße 6, 35043, Marburg, Germany
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2
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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 (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311317. [PMID: 38712469 DOI: 10.1002/smll.202311317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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3
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Chen SH, Chang SW, Chen HL. Characterization of 2D Transition Metal Dichalcogenides Through Anisotropic Exciton Behaviors. SMALL METHODS 2024; 8:e2301061. [PMID: 38098297 DOI: 10.1002/smtd.202301061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/03/2023] [Indexed: 05/18/2024]
Abstract
This study reports the first attempt to characterize the quality, defects, and strain of as-grown monolayer transition metal dichalcogenide (TMDC)-based 2D materials through exciton anisotropy. A standard ellipsometric parameter (Ψ) to observe anisotropic exciton behavior in monolayer 2D materials is used. According to the strong exciton effect from phonon-electron coupling processes, the change in the exciton in the Van Hove singularity is sensitive to lattice distortions such as defects and strain. In comparison with Raman spectroscopy, the variations in exciton anisotropy in Ψ are more sensitive for detecting slight changes in the quality and strain of monolayer TMDC films. Moreover, the optical power requirement for TMDC characterization through exciton anisotropy in Ψ is ≈10-5 mW cm-2, which is significantly less than that of Raman spectroscopy (≈106 mW cm-2). The standard deviation of the signals varies with strain (defects) in Raman spectra and exciton anisotropies in Ψ are 0.700 (0.795) and 0.033 (0.073), indicating that exciton anisotropy is more sensitive to slight changes in the quality of monolayer TMDC films.
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Affiliation(s)
- Shu-Hsien Chen
- Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Sih-Wei Chang
- Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
| | - Hsuen-Li Chen
- Department of Materials Science and Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, 10617, Taiwan
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4
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Minj A, Mootheri V, Banerjee S, Nalin Mehta A, Serron J, Hantschel T, Asselberghs I, Goux L, Kar GS, Heyns M, Lin DHC. Direct Assessment of Defective Regions in Monolayer MoS 2 Field-Effect Transistors through In Situ Scanning Probe Microscopy Measurements. ACS NANO 2024; 18:10653-10666. [PMID: 38556983 DOI: 10.1021/acsnano.4c03080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Implementing two-dimensional materials in field-effect transistors (FETs) offers the opportunity to continue the scaling trend in the complementary metal-oxide-semiconductor technology roadmap. Presently, the search for electrically active defects, in terms of both their density of energy states and their spatial distribution, has turned out to be of paramount importance in synthetic transition metal dichalcogenides layers, as they are suspected of severely inhibiting these devices from achieving their highest performance. Although advanced microscopy tools have allowed the direct detection of physical defects such as grain boundaries and point defects, their implementation at the device scale to assess the active defect distribution and their impact on field-induced channel charge modulation and current transport is strictly restrained. Therefore, it becomes critical to directly probe the gate modulation effect on the carrier population at the nanoscale of an FET channel, with the objective to establish a direct correlation with the device characteristics. Here, we have investigated the active channel in a monolayer MoS2 FET through in situ scanning probe microscopy, namely, Kelvin probe force microscopy and scanning capacitance microscopy, to directly identify active defect sites and to improve our understanding of the contribution of grain boundaries, bilayer islands, and defective grain domains to channel conductance.
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Affiliation(s)
| | - Vivek Mootheri
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Materials, KU Leuven, Kapeldreef 75, 3001 Leuven, Belgium
| | | | | | | | | | | | | | | | - Marc Heyns
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Materials, KU Leuven, Kapeldreef 75, 3001 Leuven, Belgium
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Kandybka I, Groven B, Medina Silva H, Sergeant S, Nalin Mehta A, Koylan S, Shi Y, Banerjee S, Morin P, Delabie A. Chemical Vapor Deposition of a Single-Crystalline MoS 2 Monolayer through Anisotropic 2D Crystal Growth on Stepped Sapphire Surface. ACS NANO 2024; 18:3173-3186. [PMID: 38235963 DOI: 10.1021/acsnano.3c09364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Recently, a step-flow growth mode has been proposed to break the inherent molybdenum disulfide (MoS2) crystal domain bimodality and yield a single-crystalline MoS2 monolayer on commonly employed sapphire substrates. This work reveals an alternative growth mechanism during the metal-organic chemical vapor deposition (MOCVD) of a single-crystalline MoS2 monolayer through anisotropic 2D crystal growth. During early growth stages, the epitaxial symmetry and commensurability of sapphire terraces rather than the sapphire step inclination ultimately govern the MoS2 crystal orientation. Strikingly, as the MoS2 crystals continue to grow laterally, the sapphire steps transform the MoS2 crystal geometry into diamond-shaped domains presumably by anisotropic diffusion of ad-species and facet development. Even though these MoS2 domains nucleate on sapphire with predominantly bimodal 0 and 60° azimuthal rotation, the individual domains reach lateral dimensions of up to 200 nm before merging seamlessly into a single-crystalline MoS2 monolayer upon coalescence. Plan-view transmission electron microscopy reveals the single-crystalline nature across 50 μm by 50 μm inspection areas. As a result, the median carrier mobility of MoS2 monolayers peaks at 25 cm2 V-1 s-1 with the highest value reaching 28 cm2 V-1 s-1. This work details synthesis-structure correlations and the possibilities to tune the structure and material properties through substrate topography toward various applications in nanoelectronics, catalysis, and nanotechnology. Moreover, shape modulation through anisotropic growth phenomena on stepped surfaces can provide opportunities for nanopatterning for a wide range of materials.
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Affiliation(s)
- Iryna Kandybka
- imec, Kapeldreef 75, Leuven 3001, Belgium
- Department of Chemistry KU Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | | | | | | | | | - Serkan Koylan
- imec, Kapeldreef 75, Leuven 3001, Belgium
- Quantum Solid State Physics KU Leuven, Celestijnenlaan 200D, Leuven 3001, Belgium
| | | | | | | | - Annelies Delabie
- imec, Kapeldreef 75, Leuven 3001, Belgium
- Department of Chemistry KU Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
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6
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Katiyar AK, Hoang AT, Xu D, Hong J, Kim BJ, Ji S, Ahn JH. 2D Materials in Flexible Electronics: Recent Advances and Future Prospectives. Chem Rev 2024; 124:318-419. [PMID: 38055207 DOI: 10.1021/acs.chemrev.3c00302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.
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Affiliation(s)
- Ajit Kumar Katiyar
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Duo Xu
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Juyeong Hong
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Beom Jin Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Seunghyeon Ji
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
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7
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Chen L, Cheng Z, He S, Zhang X, Deng K, Zong D, Wu Z, Xia M. Large-area single-crystal TMD growth modulated by sapphire substrates. NANOSCALE 2024; 16:978-1004. [PMID: 38112240 DOI: 10.1039/d3nr05400d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Transition metal dichalcogenides (TMDs) have recently attracted extensive attention due to their unique physical and chemical properties; however, the preparation of large-area TMD single crystals is still a great challenge. Chemical vapor deposition (CVD) is an effective method to synthesize large-area and high-quality TMD films, in which sapphires as suitable substrates play a crucial role in anchoring the source material, promoting nucleation and modulating epitaxial growth. In this review, we provide an insightful overview of different epitaxial mechanisms and growth behaviors associated with the atomic structure of sapphire surfaces and the growth parameters. First, we summarize three epitaxial growth mechanisms of TMDs on sapphire substrates, namely, van der Waals epitaxy, step-guided epitaxy, and dual-coupling-guided epitaxy. Second, we introduce the effects of polishing, cutting, and annealing processing of the sapphire surface on the TMD growth. Finally, we discuss the influence of other growth parameters, such as temperature, pressure, carrier gas, and substrate position, on the growth kinetics of TMDs. This review might provide deep insights into the controllable growth of large-area single-crystal TMDs on sapphires, which will propel their practical applications in high-performance nanoelectronics and optoelectronics.
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Affiliation(s)
- Lina Chen
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Zhaofang Cheng
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China
| | - Shaodan He
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Xudong Zhang
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Kelun Deng
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Dehua Zong
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Zipeng Wu
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
| | - Minggang Xia
- Department of Applied Physics, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China.
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China
- Shaanxi Province Key Laboratory of Quantum Information and Optoelectronic Quantum Devices, School of Physics, Xi'an Jiaotong University, 710049, People's Republic of China
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8
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Li S, Ouyang D, Zhang N, Zhang Y, Murthy A, Li Y, Liu S, Zhai T. Substrate Engineering for Chemical Vapor Deposition Growth of Large-Scale 2D Transition Metal Dichalcogenides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211855. [PMID: 37095721 DOI: 10.1002/adma.202211855] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 04/17/2023] [Indexed: 05/03/2023]
Abstract
The large-scale production of 2D transition metal dichalcogenides (TMDs) is essential to realize their industrial applications. Chemical vapor deposition (CVD) has been considered as a promising method for the controlled growth of high-quality and large-scale 2D TMDs. During a CVD process, the substrate plays a crucial role in anchoring the source materials, promoting the nucleation and stimulating the epitaxial growth. It thus significantly affects the thickness, microstructure, and crystal quality of the products, which are particularly important for obtaining 2D TMDs with expected morphology and size. Here, an insightful review is provided by focusing on the recent development associated with the substrate engineering strategies for CVD preparation of large-scale 2D TMDs. First, the interaction between 2D TMDs and substrates, a key factor for the growth of high-quality materials, is systematically discussed by combining the latest theoretical calculations. Based on this, the effect of various substrate engineering approaches on the growth of large-area 2D TMDs is summarized in detail. Finally, the opportunities and challenges of substrate engineering for the future development of 2D TMDs are discussed. This review might provide deep insight into the controllable growth of high-quality 2D TMDs toward their industrial-scale practical applications.
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Affiliation(s)
- Shaohua Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Decai Ouyang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Na Zhang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yi Zhang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Akshay Murthy
- Superconducting Quantum Materials and Systems Division, Fermi National Accelerator Laboratory (FNAL), Batavia, IL, 60510, USA
| | - Yuan Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518057, P. R. China
| | - Shiyuan Liu
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, 518057, P. R. China
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9
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Fu JH, Min J, Chang CK, Tseng CC, Wang Q, Sugisaki H, Li C, Chang YM, Alnami I, Syong WR, Lin C, Fang F, Zhao L, Lo TH, Lai CS, Chiu WS, Jian ZS, Chang WH, Lu YJ, Shih K, Li LJ, Wan Y, Shi Y, Tung V. Oriented lateral growth of two-dimensional materials on c-plane sapphire. NATURE NANOTECHNOLOGY 2023; 18:1289-1294. [PMID: 37474684 DOI: 10.1038/s41565-023-01445-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 06/08/2023] [Indexed: 07/22/2023]
Abstract
Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) represent the ultimate thickness for scaling down channel materials. They provide a tantalizing solution to push the limit of semiconductor technology nodes in the sub-1 nm range. One key challenge with 2D semiconducting TMD channel materials is to achieve large-scale batch growth on insulating substrates of single crystals with spatial homogeneity and compelling electrical properties. Recent studies have claimed the epitaxy growth of wafer-scale, single-crystal 2D TMDs on a c-plane sapphire substrate with deliberately engineered off-cut angles. It has been postulated that exposed step edges break the energy degeneracy of nucleation and thus drive the seamless stitching of mono-oriented flakes. Here we show that a more dominant factor should be considered: in particular, the interaction of 2D TMD grains with the exposed oxygen-aluminium atomic plane establishes an energy-minimized 2D TMD-sapphire configuration. Reconstructing the surfaces of c-plane sapphire substrates to only a single type of atomic plane (plane symmetry) already guarantees the single-crystal epitaxy of monolayer TMDs without the aid of step edges. Electrical results evidence the structural uniformity of the monolayers. Our findings elucidate a long-standing question that curbs the wafer-scale batch epitaxy of 2D TMD single crystals-an important step towards using 2D materials for future electronics. Experiments extended to perovskite materials also support the argument that the interaction with sapphire atomic surfaces is more dominant than step-edge docking.
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Affiliation(s)
- Jui-Han Fu
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Jiacheng Min
- Department of Civil Engineering, The University of Hong Kong, Hong Kong, China
| | - Che-Kang Chang
- Department of Electrophysics, National Yang-Ming Chiao Tung University, Hsinchu, Taiwan
| | - Chien-Chih Tseng
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Qingxiao Wang
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Hayato Sugisaki
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Chenyang Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Yu-Ming Chang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Ibrahim Alnami
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Wei-Ren Syong
- Research Centre for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Ci Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China
| | - Feier Fang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China
| | - Lv Zhao
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China
| | - Tzu-Hsuan Lo
- Department of Electrophysics, National Yang-Ming Chiao Tung University, Hsinchu, Taiwan
| | - Chao-Sung Lai
- Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Sheng Chiu
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Zih-Siang Jian
- Department of Electrophysics, National Yang-Ming Chiao Tung University, Hsinchu, Taiwan
| | - Wen-Hao Chang
- Department of Electrophysics, National Yang-Ming Chiao Tung University, Hsinchu, Taiwan
- Research Centre for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Yu-Jung Lu
- Research Centre for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Kaimin Shih
- Department of Civil Engineering, The University of Hong Kong, Hong Kong, China
| | - Lain-Jong Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
| | - Yi Wan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
| | - Yumeng Shi
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China.
| | - Vincent Tung
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan.
- Center for Green Technology of the Chang Gung University, Taoyuan, Taiwan.
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10
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Romanov RI, Zabrosaev IV, Chouprik AA, Yakubovsky DI, Tatmyshevskiy MK, Volkov VS, Markeev AM. Temperature-Dependent Structural and Electrical Properties of Metal-Organic CVD MoS 2 Films. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2712. [PMID: 37836353 PMCID: PMC10574732 DOI: 10.3390/nano13192712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 10/15/2023]
Abstract
Metal-Organic CVD method (MOCVD) allows for deposition of ultrathin 2D transition metal dichalcogenides (TMD) films of electronic quality onto wafer-scale substrates. In this work, the effect of temperature on structure, chemical states, and electronic qualities of the MOCVD MoS2 films were investigated. The results demonstrate that the temperature increase in the range of 650 °C to 950 °C results in non-monotonic average crystallite size variation. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman spectroscopy investigation has established the film crystal structure improvement with temperature increase in this range. At the same time, X-Ray photoelectron spectroscopy (XPS) method allowed to reveal non-stoichiometric phase fraction increase, corresponding to increased sulfur vacancies (VS) concentration from approximately 0.9 at.% to 3.6 at.%. Established dependency between the crystallite domains size and VS concentration suggests that these vacancies are form predominantly at the grain boundaries. The results suggest that an increased Vs concentration and enhanced charge carriers scattering at the grains' boundaries should be the primary reasons of films' resistivity increase from 4 kΩ·cm to 39 kΩ·cm.
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Affiliation(s)
- Roman I. Romanov
- Center of Shared Research Facilities, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141701, Russia; (R.I.R.); (I.V.Z.); (A.A.C.)
| | - Ivan V. Zabrosaev
- Center of Shared Research Facilities, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141701, Russia; (R.I.R.); (I.V.Z.); (A.A.C.)
| | - Anastasia A. Chouprik
- Center of Shared Research Facilities, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141701, Russia; (R.I.R.); (I.V.Z.); (A.A.C.)
| | - Dmitry I. Yakubovsky
- Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141700, Russia; (D.I.Y.); (M.K.T.); (V.S.V.)
| | - Mikhail K. Tatmyshevskiy
- Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141700, Russia; (D.I.Y.); (M.K.T.); (V.S.V.)
| | - Valentyn S. Volkov
- Center for Photonics & 2D Materials, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141700, Russia; (D.I.Y.); (M.K.T.); (V.S.V.)
| | - Andrey M. Markeev
- Center of Shared Research Facilities, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny 141701, Russia; (R.I.R.); (I.V.Z.); (A.A.C.)
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11
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Kim JY, Ju X, Ang KW, Chi D. Van der Waals Layer Transfer of 2D Materials for Monolithic 3D Electronic System Integration: Review and Outlook. ACS NANO 2023; 17:1831-1844. [PMID: 36655854 DOI: 10.1021/acsnano.2c10737] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional materials (2DMs) have attracted a great deal of interest due to their immense potential for scientific breakthroughs and technological innovations. While some 2D transition metal dichalcogenides (TMDC) such as MoS2 and WS2 are considered as the ultimate channel materials in unltrascaled transistors as replacements for Si, there has also been increasing interest in the monolithic 3D integration of 2DMs on the Si CMOS platform or in flexible electronics as back-end-of-line transistors, memory devices/selectors, and sensors, taking advantage of 2DM properties such as a high current driving capability with low leakage current, nonvolatile switching characteristics, a large surface-to-volume ratio, and a tunable bandgap. However, the realization of both of these scenarios critically depends on the development of manufacturing-viable high-yield 2DM layers transfer from the growth substrate to the Si, since the growth of high-quality 2DM layers often requires a high-temperature growth process on template substrates. Motivated by this, extensive efforts have been made by the 2DM research community to develop various 2DM layer transfer methods, leveraging the van der Waals transfer capability of the layer-structured 2DMs. These efforts have led to a number of successful demonstrations of wafer-scale 2D TMDC layer transfer, while 2DM-enabled template growth/transfer of some functional bulk materials such as III-V, Ge, and AlN has also been demonstrated. This review surveys and compares different 2DM transfer methods developed recently, with a focus on large-area 2D TMDC film transfer along with an introduction of 2DM template-assisted van der Waals growth/transfer of non-2D thin films. We will also briefly present an outlook of our envisioned multifunctionalities in 3D integrated electronic systems enabled by monolithic 3D integration of 2DMs and III-V via van der Waals transfer and discuss possible technology options for overcoming remaining challenges.
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Affiliation(s)
- Jun-Young Kim
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Xin Ju
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Kah-Wee Ang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 2 Fusionopolis Way, Singapore 138634, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Dongzhi Chi
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 2 Fusionopolis Way, Singapore 138634, Singapore
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12
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Zheng W, Saiz F, Shen Y, Zhu K, Liu Y, McAleese C, Conran B, Wang X, Lanza M. Defect-Free Metal Deposition on 2D Materials via Inkjet Printing Technology. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104138. [PMID: 34734445 DOI: 10.1002/adma.202104138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/30/2021] [Indexed: 06/13/2023]
Abstract
2D materials have many outstanding properties that make them attractive for the fabrication of electronic devices, such as high conductivity, flexibility, and transparency. However, integrating 2D materials in commercial devices and circuits is challenging because their structure and properties can be damaged during the fabrication process. Recent studies have demonstrated that standard metal deposition techniques (like electron beam evaporation and sputtering) significantly damage the atomic structure of 2D materials. Here it is shown that the deposition of metal via inkjet printing technology does not produce any observable damage in the atomic structure of ultrathin 2D materials, and it can keep a sharp interface. These conclusions are supported by abundant data obtained via atomistic simulations, transmission electron microscopy, nanochemical metrology, and device characterization in a probe station. The results are important for the understanding of inkjet printing technology applied to 2D materials, and they could contribute to the better design and optimization of electronic devices and circuits.
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Affiliation(s)
- Wenwen Zheng
- Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren-Ai Road, Suzhou, 215123, China
| | - Fernan Saiz
- Institute of Material Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Yaqing Shen
- Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren-Ai Road, Suzhou, 215123, China
| | - Kaichen Zhu
- MIND, Department of Electronic and Biomedical Engineering, Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028, Spain
| | - Yingwen Liu
- Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 199 Ren-Ai Road, Suzhou, 215123, China
| | - Clifford McAleese
- Aixtron Ltd, Anderson Road, Buckingway Business Park, Swavesy, CB24 4FQ, UK
| | - Ben Conran
- Aixtron Ltd, Anderson Road, Buckingway Business Park, Swavesy, CB24 4FQ, UK
| | - Xiaochen Wang
- Aixtron Ltd, Anderson Road, Buckingway Business Park, Swavesy, CB24 4FQ, UK
| | - Mario Lanza
- Institute of Material Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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13
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Zhang B, Yun C, Wu H, Zhao Z, Zeng Y, Liang D, Shen T, Zhang J, Huang X, Song J, Xu J, Zhang Q, Tan PH, Gao S, Hou Y. Two-Dimensional Wedge-Shaped Magnetic EuS: Insight into the Substrate Step-Guided Epitaxial Synthesis on Sapphire. J Am Chem Soc 2022; 144:19758-19769. [PMID: 36257067 DOI: 10.1021/jacs.2c06023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rare earth chalcogenides (RECs) with novel luminescence and magnetic properties offer fascinating opportunities for fundamental research and applications. However, controllable synthesis of RECs down to the two-dimensional (2D) limit still has a great challenge. Herein, 2D wedge-shaped ferromagnetic EuS single crystals are successfully synthesized via a facile molten-salt-assisted chemical vapor deposition method on sapphire. Based on the theoretical simulations and experimental measurements, the mechanisms of aligned growth and wedge-shaped growth are systematically proposed. The wedge-shaped growth is driven by a dual-interaction mechanism, where the coupling between EuS and the substrate steps impedes the lateral growth, and the strong bonding of nonlayered EuS itself facilitates the vertical growth. Through temperature-dependent Raman and photoluminescence characterization, the nanoflakes show a large Raman temperature coefficient of -0.030 cm-1 K-1 and uncommon increasing band gap with temperature. More importantly, by low-temperature magnetic force microscopy characterization, thickness variation of the magnetic signal is revealed within one sample, indicating the great potential of the wedge-shaped nanoflake to serve as a platform for highly efficient investigation of thickness-dependent magnetic properties. This work sheds new light on 2D RECs and will offer a deep understanding of 2D wedge-shaped materials.
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Affiliation(s)
- Biao Zhang
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Chao Yun
- State Key Laboratory for Mesoscopic Physics, School of Physics, Beijing Key Laboratory for Magnetoeletric Materials and Devices, Peking University, Beijing100871, China
| | - Heng Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Zijing Zhao
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Yi Zeng
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Dong Liang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Beijing Key Laboratory for Magnetoeletric Materials and Devices, Peking University, Beijing100871, China
| | - Tong Shen
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Jine Zhang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing100191, China
| | - Xiaoxiao Huang
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Jiepeng Song
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Junjie Xu
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing100871, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing100083, China
| | - Song Gao
- Institute of Spin-X Science and Technology, South China University of Technology, Guangzhou510641, China
| | - Yanglong Hou
- School of Materials Science and Engineering, Peking University, Beijing100871, China.,Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing100871, China
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14
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Lanza M, Waser R, Ielmini D, Yang JJ, Goux L, Suñe J, Kenyon AJ, Mehonic A, Spiga S, Rana V, Wiefels S, Menzel S, Valov I, Villena MA, Miranda E, Jing X, Campabadal F, Gonzalez MB, Aguirre F, Palumbo F, Zhu K, Roldan JB, Puglisi FM, Larcher L, Hou TH, Prodromakis T, Yang Y, Huang P, Wan T, Chai Y, Pey KL, Raghavan N, Dueñas S, Wang T, Xia Q, Pazos S. Standards for the Characterization of Endurance in Resistive Switching Devices. ACS NANO 2021; 15:17214-17231. [PMID: 34730935 DOI: 10.1021/acsnano.1c06980] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Resistive switching (RS) devices are emerging electronic components that could have applications in multiple types of integrated circuits, including electronic memories, true random number generators, radiofrequency switches, neuromorphic vision sensors, and artificial neural networks. The main factor hindering the massive employment of RS devices in commercial circuits is related to variability and reliability issues, which are usually evaluated through switching endurance tests. However, we note that most studies that claimed high endurances >106 cycles were based on resistance versus cycle plots that contain very few data points (in many cases even <20), and which are collected in only one device. We recommend not to use such a characterization method because it is highly inaccurate and unreliable (i.e., it cannot reliably demonstrate that the device effectively switches in every cycle and it ignores cycle-to-cycle and device-to-device variability). This has created a blurry vision of the real performance of RS devices and in many cases has exaggerated their potential. This article proposes and describes a method for the correct characterization of switching endurance in RS devices; this method aims to construct endurance plots showing one data point per cycle and resistive state and combine data from multiple devices. Adopting this recommended method should result in more reliable literature in the field of RS technologies, which should accelerate their integration in commercial products.
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Affiliation(s)
- Mario Lanza
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Rainer Waser
- Peter-Grünberg-Institut (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Peter-Grünberg-Institut (PGI-10), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institut für Werkstoffe der Elektrotechnik 2 (IWE2), RWTH Aachen University, Aachen 52074, Germany
| | - Daniele Ielmini
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano and IU.NET, Piazza L. da Vinci 32, Milano, 20133, Italy
| | - J Joshua Yang
- Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, California 90089, United States
| | | | - Jordi Suñe
- Departament d'Enginyeria Electrònica, Universitat Autònoma de Barcelona, Barcelona 08193, Spain
| | - Anthony Joseph Kenyon
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | - Adnan Mehonic
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | - Sabina Spiga
- CNR-IMM, Unit of Agrate Brianza, Via C. Olivetti 2, Agrate Brianza (MB) 20864, Italy
| | - Vikas Rana
- Peter-Grünberg-Institut (PGI-10), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stefan Wiefels
- Peter-Grünberg-Institut (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stephan Menzel
- Peter-Grünberg-Institut (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Ilia Valov
- Peter-Grünberg-Institut (PGI-7), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Marco A Villena
- Applied Materials Inc., Via Ruini, Reggio Emilia 74L 42122, Italy
| | - Enrique Miranda
- Departament d'Enginyeria Electrònica, Universitat Autònoma de Barcelona, Barcelona 08193, Spain
| | - Xu Jing
- School of Materials Science and Engineering, Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189, China
| | - Francesca Campabadal
- Institut de Microelectrònica de Barcelona-Centre Nacional de Microelectrònica, Consejo Superior de Investigaciones Científicas, Bellaterra 08193, Spain
| | - Mireia B Gonzalez
- Institut de Microelectrònica de Barcelona-Centre Nacional de Microelectrònica, Consejo Superior de Investigaciones Científicas, Bellaterra 08193, Spain
| | - Fernando Aguirre
- Unidad de Investigación y Desarrollo de las Ingenierías-CONICET, Facultad Regional Buenos Aires, Universidad Tecnológica Nacional (UIDI-CONICET/FRBA-UTN), Buenos Aires, Medrano 951(C1179AAQ), Argentina
| | - Felix Palumbo
- Unidad de Investigación y Desarrollo de las Ingenierías-CONICET, Facultad Regional Buenos Aires, Universidad Tecnológica Nacional (UIDI-CONICET/FRBA-UTN), Buenos Aires, Medrano 951(C1179AAQ), Argentina
| | - Kaichen Zhu
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Juan Bautista Roldan
- Departamento de Electrónica y Tecnología de Computadores, Facultad de Ciencias, Universidad de Granada, Avd. Fuentenueva s/n, Granada 18071, Spain
| | - Francesco Maria Puglisi
- Dipartimento di Ingegneria "Enzo Ferrari", Università di Modena e Reggio Emilia, Via P. Vivarelli 10/1, Modena 41125, Italy
| | - Luca Larcher
- Applied Materials Inc., Via Ruini, Reggio Emilia 74L 42122, Italy
| | - Tuo-Hung Hou
- Department of Electronics Engineering and Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Themis Prodromakis
- Centre for Electronics Frontiers, University of Southampton, Southampton SO171BJ, United Kingdom
| | - Yuchao Yang
- Key Laboratory of Microelectronic Devices and Circuits (MOE), Department of Micro/nanoelectronics, Peking University, Beijing 100871, China
| | - Peng Huang
- Key Laboratory of Microelectronic Devices and Circuits (MOE), Department of Micro/nanoelectronics, Peking University, Beijing 100871, China
| | - Tianqing Wan
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Yang Chai
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Kin Leong Pey
- Engineering Product Development, Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
| | - Nagarajan Raghavan
- Engineering Product Development, Singapore University of Technology and Design (SUTD), 8 Somapah Road, 487372 Singapore
| | - Salvador Dueñas
- Department of Electronics, University of Valladolid, Paseo de Belén 15, Valladolid E-47011, Spain
| | - Tao Wang
- Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University 199 Ren-Ai Road, Suzhou 215123, China
| | - Qiangfei Xia
- Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, Massachusetts 01003-9292, United States
| | - Sebastian Pazos
- Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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