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Zacharias M, Kelires PC. Quantum Confinement of Electron-Phonon Coupling in Graphene Quantum Dots. J Phys Chem Lett 2021; 12:9940-9946. [PMID: 34614351 DOI: 10.1021/acs.jpclett.1c02899] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
On the basis of first-principles calculations and the special displacement method, we demonstrate the quantum confinement scaling law of the phonon-induced gap renormalization of graphene quantum dots (GQDs). We employ zigzag-edged GQDs with hydrogen passivation and embedded in hexagonal boron nitride. Our calculations for GQDs in the sub-10 nm region reveal strong quantum confinement of the zero-point renormalization ranging from 20 to 250 meV. To obtain these values we introduce a correction to the Allen-Heine theory of temperature-dependent energy levels that arises from the phonon-induced splitting of 2-fold degenerate edge states. This correction amounts to more than 50% of the gap renormalization. We also present momentum-resolved spectral functions of GQDs, which are not reported in previous contributions. Our results lay the foundation to systematically engineer temperature-dependent electronic structures of GQDs for applications in solar cells, electronic transport, and quantum computing devices.
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Affiliation(s)
- Marios Zacharias
- Research Unit for Nanostructured Materials Systems, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol, Cyprus
- Department of Mechanical and Materials Science Engineering, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol, Cyprus
| | - Pantelis C Kelires
- Research Unit for Nanostructured Materials Systems, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol, Cyprus
- Department of Mechanical and Materials Science Engineering, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol, Cyprus
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2
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Deng Y, Zhuang X, Wang W, Gu R, He D, Wang L, Cheng X. Direct visualization of beam-resist interaction volume for sub-nanometer helium ion beam-lithography. NANOTECHNOLOGY 2021; 32:415302. [PMID: 34198269 DOI: 10.1088/1361-6528/ac1099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/01/2021] [Indexed: 06/13/2023]
Abstract
Interaction volume of beam-resist is a basis unit of beam-lithography, directly determines the critical parameters of beam-lithography. We have visualized the interaction volume at the state-of-the-art sub-10 nm scale by a spot irradiation of sub-nanometer helium ion beam into an approximately free-standing resist. The visualized interaction volume suggests helium ion beam has an excellent capability in nanofabrication. Specifically, helium ion beam-lithography is 1000 times more efficient than electron beam-lithography (EBL), owns a sub-4 nm resolution, can achieve a large pattern aspect ratio (greater than 8), and does not suffer from backscattering effect at a normal exposure dose. Furthermore, the interaction volume has been theoretically studied by considering the spatial distribution of energy deposited in the resist, and eventually lead to a model for pattern prediction and proximity effect corrections. We expect that, our approach to visualize the interaction volume may be applied to study other high resolution lithographic techniques such as x-ray lithography and EBL, and it may open new possibilities in other applications, like beam-imaging, beam-milling, and beam-modification.
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Affiliation(s)
- Yunsheng Deng
- Pico Center and SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Xin Zhuang
- Shenzhen Key Laboratory for Nanoimprint Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
- Department of Mechanical Engineering, the University of Hong Kong, Hong Kong
- HKU-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, Zhejiang 311300, People's Republic of China
| | - Wu Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
| | - Rui Gu
- Pico Center and SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Dongsheng He
- Pico Center and SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Liqiu Wang
- Department of Mechanical Engineering, the University of Hong Kong, Hong Kong
- HKU-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, Zhejiang 311300, People's Republic of China
| | - Xing Cheng
- Pico Center and SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
- Shenzhen Key Laboratory for Nanoimprint Technology, Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
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3
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Allen FI. A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:633-664. [PMID: 34285866 PMCID: PMC8261528 DOI: 10.3762/bjnano.12.52] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/30/2021] [Indexed: 05/28/2023]
Abstract
The helium ion microscope has emerged as a multifaceted instrument enabling a broad range of applications beyond imaging in which the finely focused helium ion beam is used for a variety of defect engineering, ion implantation, and nanofabrication tasks. Operation of the ion source with neon has extended the reach of this technology even further. This paper reviews the materials modification research that has been enabled by the helium ion microscope since its commercialization in 2007, ranging from fundamental studies of beam-sample effects, to the prototyping of new devices with features in the sub-10 nm domain.
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Affiliation(s)
- Frances I Allen
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
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4
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Su S, Wang X, Xue J. Nanopores in two-dimensional materials: accurate fabrication. MATERIALS HORIZONS 2021; 8:1390-1408. [PMID: 34846448 DOI: 10.1039/d0mh01412e] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) materials such as graphene and molybdenum disulfide have been demonstrated with a wide range of applications in electronic devices, chemical catalysis, single-molecule detection, and energy conversion. In the 2D materials, nanopores can be created, and the 2D nanoporous membranes possess many unique properties such as ultrathin thickness, high surface area, and excellent particle sieving capability, showing extraordinary promise in plenty of applications, such as sea water desalination, gas separation, and DNA sequencing. The performances of these membranes are mainly determined by the nanopore size, structure, and density, which, in turn, rely on the fabrication techniques of the nanopores. This review covers the important progress of nanopore fabrication in 2D materials and comprehensively compares these methods for the features of the introduced nanopores and their formation processes. Future perspectives are discussed on the opportunities and challenges in fabricating high-grade 2D nanopores.
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Affiliation(s)
- Shihao Su
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, P. R. China.
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5
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Saraswat V, Jacobberger RM, Arnold MS. Materials Science Challenges to Graphene Nanoribbon Electronics. ACS NANO 2021; 15:3674-3708. [PMID: 33656860 DOI: 10.1021/acsnano.0c07835] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Graphene nanoribbons (GNRs) have recently emerged as promising candidates for channel materials in future nanoelectronic devices due to their exceptional electronic, thermal, and mechanical properties and chemical inertness. However, the adoption of GNRs in commercial technologies is currently hampered by materials science and integration challenges pertaining to synthesis and devices. In this Review, we present an overview of the current status of challenges, recent breakthroughs toward overcoming these challenges, and possible future directions for the field of GNR electronics. We motivate the need for exploration of scalable synthetic techniques that yield atomically precise, placed, registered, and oriented GNRs on CMOS-compatible substrates and stimulate ideas for contact and dielectric engineering to realize experimental performance close to theoretically predicted metrics. We also briefly discuss unconventional device architectures that could be experimentally investigated to harness the maximum potential of GNRs in future spintronic and quantum information technologies.
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Affiliation(s)
- Vivek Saraswat
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Robert M Jacobberger
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Michael S Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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6
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Luan B, Kuroda MA. Electrophoretic Transport of Single-Stranded DNA through a Two Dimensional Nanopore Patterned on an In-Plane Heterostructure. ACS NANO 2020; 14:13137-13145. [PMID: 32902252 DOI: 10.1021/acsnano.0c04743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent advances in nanotechnology have facilitated fabrication of various solid state nanopores as a versatile alternative to biological nanopores; however, effective transport of a single-stranded DNA (ssDNA) molecule through solid state nanopores for sequencing has remained a challenge. In particular, the nonspecific interactions between the ssDNA and the engineered nanopore surface are known to impose difficulties on both transport and interrogation. Here, we show that a two-dimensional (2D) nanopore patterned on an in-plane heterostructure comprising both graphene and hexagonal boron nitride (hBN) can be utilized to transport the ssDNA electrophoretically. Energetically, a ssDNA molecule prefers to stay on the hBN domain than the graphene one since the former has a stronger van der Waals attraction with the ssDNA, as demonstrated in both classic molecular dynamics (MD) simulations and density functional theory (DFT) based calculations, which leads to the confinement of the ssDNA in the 2D nanopore. Therefore, this nanopore enables the manipulation of the conformation of a highly flexible ssDNA molecule on a flat 2D heterostructure surface, making it possible for sensing ssDNA bases using the high resolution atomic force microscopy (AFM) or scanning tunneling microscopy (STM) in the third dimension (perpendicular to the 2D surface).
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Affiliation(s)
- Binquan Luan
- Computational Biological Center, IBM Thomas J. Watson Research, Yorktown Heights, New York 10598, United States
| | - Marcelo A Kuroda
- Department of Physics, Auburn University, Auburn, Alabama 36849, United States
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Petrov YV, Grigoryev EA, Baraban AP. Helium focused ion beam irradiation with subsequent chemical etching for the fabrication of nanostructures. NANOTECHNOLOGY 2020; 31:215301. [PMID: 31978916 DOI: 10.1088/1361-6528/ab6fe3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this paper we demonstrate a nanofabrication technique based on local ion irradiation of silicon dioxide with a focused helium ion beam. The wet etching of silicon dioxide irradiated with a focused helium ion beam is described in a two-dimensional case both numerically and experimentally. We suggest a model for the etching process based on the distribution of ion induced defects in the irradiated material. The profile of the surface of the etched silicon dioxide is simulated and compared with the results from scanning electron microscopy. Fabrication of a suspended nanostring with a diameter of less than 20 nm by means of etching ion-irradiated material is demonstrated.
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Wang Z, Luo R, Johnson I, Kashani H, Chen M. Inlaid ReS 2 Quantum Dots in Monolayer MoS 2. ACS NANO 2020; 14:899-906. [PMID: 31825587 DOI: 10.1021/acsnano.9b08186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are prospective materials for quantum devices owing to their inherent 2D confinements. They also provide a platform to realize even lower-dimensional in-plane electron confinement, for example, 0D quantum dots, for exotic physical properties. However, fabrication of such laterally confined monolayer (1L) nanostructure in 1L crystals remains challenging. Here we report the realization of 1L ReS2 quantum dots epitaxially inlaid in 1L MoS2 by a two-step chemical vapor deposition method combining with plasma treatment. The lateral lattice mismatch between ReS2 and MoS2 leads to size-dependent crystal structure evolution and in-plane straining of the 1L ReS2 quantum dots. Optical spectroscopies reveal the abnormal charge transfer between the 1L ReS2 quantum dots and the MoS2 matrix, resulting from electron trapping in the 1L ReS2 quantum dots. This study may shed light on the development of in-plane quantum-confined devices in 2D materials for potential applications in quantum information.
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Affiliation(s)
- Ziqian Wang
- Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Ruichun Luo
- Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Isaac Johnson
- Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Hamzeh Kashani
- Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
| | - Mingwei Chen
- Department of Materials Science and Engineering , Johns Hopkins University , Baltimore , Maryland 21218 , United States
- WPI Advanced Institute for Materials Research , Tohoku University , Sendai 980-8577 , Japan
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Abdelsalam H, O. Younis W, Saroka VA, Teleb NH, Yunoki S, Zhang Q. Interaction of hydrated metals with chemically modified hexagonal boron nitride quantum dots: wastewater treatment and water splitting. Phys Chem Chem Phys 2020; 22:2566-2579. [DOI: 10.1039/c9cp06823f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The electronic and adsorption properties of chemically modified square hexagonal boron nitride quantum dots are investigated using density functional theory calculations.
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Affiliation(s)
- H. Abdelsalam
- School of Materials Science and Engineering
- Yancheng Institute of Technology
- Yancheng 224051
- P. R. China
- Theoretical Physics Department
| | - W. O. Younis
- Vice Presidency for Postgraduate Studies and Scientific Research
- Imam Abdulrahman Bin Faisal University
- Dammam
- Saudi Arabia
| | - V. A. Saroka
- Institute for Nuclear Problems
- Belarusian State University
- 220030 Minsk
- Belarus
- Center for Quantum Spintronics
| | - N. H. Teleb
- Electron Microscope and Thin Films Department
- National Research Centre
- Giza
- Egypt
| | - S. Yunoki
- Computational Condensed Matter Physics Laboratory
- RIKEN
- Wako
- Japan
| | - Q. Zhang
- School of Materials Science and Engineering
- Yancheng Institute of Technology
- Yancheng 224051
- P. R. China
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10
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Liu P, Tian H, Windl W, Gu G, Duscher G, Wu Y, Zhao M, Guo J, Xu B, Liu L. Direct imaging of the nitrogen-rich edge in monolayer hexagonal boron nitride and its band structure tuning. NANOSCALE 2019; 11:20676-20684. [PMID: 31642456 DOI: 10.1039/c9nr07147d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Identification of edge atoms and tracking the edge structure evolution of two-dimensional (2D) crystals at the scale of individual atoms is critical for understanding the edge-dominated properties and behavioral responses to external field stimuli. Here, direct imaging of the edge configuration of monolayer hexagonal boron nitride (h-BN) is demonstrated at the atomic scale, by using aberration-corrected transmission electron microscopy. Tracking of the edge atoms revealed that a nitrogen-terminated zigzag arrangement dominates along the edge, naturally leading to nitrogen rich (N-rich) characteristics in this area, while the stoichiometric interior of the h-BN monolayer is maintained. Both top-down fabrication and bottom-up growth were proposed to obtain novel h-BN flakes with an N-rich ratio larger than 1% when the size is reduced to the threshold of 25 nm. Furthermore, density functional theory calculations revealed that a new bandgap of ∼3 eV is created by the N-rich characteristics, and h-BN transforms into an n-type semiconductor by self-doping. The results call for the development of ultra-small h-BN islands to be used in intriguing 2D electronic devices with a photoresponse function to visible light.
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Affiliation(s)
- Peizhi Liu
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Huifeng Tian
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Wolfgang Windl
- Department of Materials Science and Engineering, Ohio State University, Columbus, OH 43210, USA
| | - Gong Gu
- Department of Electrical Engineering and Computer Science, the University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Gerd Duscher
- Department of Materials Science and Engineering, the University of Tennessee, Knoxville, TN 37996, USA and Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Yucheng Wu
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Min Zhao
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Junjie Guo
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China.
| | - Bingshe Xu
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China. and Materials Institute of Atomic and Molecular Science, Shaanxi University of Science & Technology, Xi'An 710021, China
| | - Lei Liu
- Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
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