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Ye Q, Tang S, Du Y, Liu Z, Wu Q, Xiao X. Electric-field-controlled electronic structures and quantum transport in monolayer InSe nanoribbons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:365501. [PMID: 38830373 DOI: 10.1088/1361-648x/ad53b4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 06/03/2024] [Indexed: 06/05/2024]
Abstract
Electronic structures and quantum transport properties of the monolayer InSe nanoribbons are studied by adopting the tight-binding model in combination with the lattice Green function method. Besides the normal bulk and edge electronic states, a unique electronic state dubbed as edge-surface is found in the InSe nanoribbon with zigzag edge type. In contrast to the zigzag InSe nanoribbon, a singular electronic state termed as bulk-surface is observed along with the normal bulk and edge electronic states in the armchair InSe nanoribbons. Moreover, the band gap, the transversal electron probability distributions in the two sublayers, and the electronic state of the topmost valence subband can be manipulated by adding a perpendicular electric field to the InSe nanoribbon. Further study shows that the charge conductance of the two-terminal monolayer InSe nanoribbons can be switched on or off by varying the electric field strength. In addition, the transport of the bulk electronic state is delicate to even a weak disorder strength, however, that of the edge and edge-surface electronic states shows a strong robustness against to the disorders. These findings may be helpful to understand the electronic characteristics of the InSe nanostructures and broaden their potential applications in two-dimensional nanoelectronic devices as well.
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Affiliation(s)
- Qian Ye
- School of Computer Science, Jiangxi University of Chinese Medicine, Nanchang 330004, People's Republic of China
| | - Shunxi Tang
- School of Computer Science, Jiangxi University of Chinese Medicine, Nanchang 330004, People's Republic of China
| | - Yan Du
- School of Computer Science, Jiangxi University of Chinese Medicine, Nanchang 330004, People's Republic of China
| | - Zhengfang Liu
- School of Basic Science, East China Jiaotong University, Nanchang 330013, People's Republic of China
| | - Qingping Wu
- School of Basic Science, East China Jiaotong University, Nanchang 330013, People's Republic of China
| | - Xianbo Xiao
- School of Computer Science, Jiangxi University of Chinese Medicine, Nanchang 330004, People's Republic of China
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2
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Deng Z. Angle-Dependent Raman Spectra of Crystal Polymorphs of GaO: A Computational Study. Chemphyschem 2024; 25:e202300129. [PMID: 38095211 DOI: 10.1002/cphc.202300129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 12/13/2023] [Indexed: 01/25/2024]
Abstract
Two crystal polymorphs of GaO consisting of GaO-H and GaO-T monolayers are proposed in this study. Based on the density functional theory calculations, the phonon dispersion demonstrates that both GaO-H and GaO-T monolayers could be stable. The band gaps of GaO-H and GaO-T monolayers are 1.51 and 1.43 eV, respectively. When an external electric field is applied, the band gaps of GaO monolayers are reduced dramatically, down to 0.13 eV with the field of 0.7 V/Å. Because of the decreased symmetry of C3v under an external electric field, more peaks of Raman spectra can be obtained. The angle-dependent Raman spectra ofA ' 1 1 ${{\rm{A}}{{^\prime}}_1^1 }$ andA ' 1 2 ${{\rm{A}}{{^\prime}}_1^2 }$ of GaO-H monolayer, andA 1 g 1 ${{\rm{A}}_{1{\rm{g}}}^1 }$ andA 1 g 2 ${{\rm{A}}_{1{\rm{g}}}^2 }$ of GaO-T monolayer are discussed seperately, with the incident lasers of 488 and 532 nm. Additionally, the Raman intensity distribution shows that the incident light should be parallel to the plane of the GaO monolayer to obtain more comparable Raman spectra. These investigations of the crystal polymorphs of GaO monolayers may guide the experimental investigations of GaO monolayers and potential optoelectronic applications.
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Affiliation(s)
- Zexiang Deng
- School of Science, Guilin University of Aerospace Technology, Guilin, 541004, China
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3
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Bikerouin M, Chdil O, Balli M. Solar cells based on 2D Janus group-III chalcogenide van der Waals heterostructures. NANOSCALE 2023; 15:7126-7138. [PMID: 37000599 DOI: 10.1039/d2nr06200c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Janus monolayers, realized by breaking the vertical structural symmetry of two-dimensional (2D) materials, pave the way for a new era of high-quality and high-performance atomically-thin vertical p-n heterojunction solar cells. Herein, employing first-principles computations, Janus group-III chalcogenide monolayers, MX, M2XY, MM'X2 and MM'XY (M, M' = Ga, In; X, Y = S, Se, Te), are deeply investigated in view of their implementation in 2D photovoltaic systems. Their stability analysis reveals that the 21 investigated monolayers are energetically, thermodynamically, mechanically, dynamically, and thermally stable, confirming their growth feasibility under ambient conditions. Furthermore, owing to their optimal band gap, high charge carrier mobilities, and strong light absorption, 2D Janus group-III monolayers are predicted as promising candidates for 2D excitonic solar cell applications. In fact, 46 type-II van der Waals (vdW) heterostructures with a lattice mismatch of less than 5% are identified by analyzing the band alignments of the investigated monolayers obtained through the HSE + SOC approach. In particular, 7 vertical vdW heterojunctions with a power conversion efficiency (PCE) higher than 20% are predicted and might be the focus of future experimental and theoretical studies. To further confirm the type II band alignment, the Ga2STe-GaInS2 vdW heterostructure, which reveals the highest PCE of 23.69%, is thoroughly investigated. Our results not only predict and evaluate stable 2D Janus group-III chalcogenide monolayers and vdW heterostructures, but also suggest that they could be used as materials for next-generation optoelectronic and photovoltaic devices.
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Affiliation(s)
- M Bikerouin
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
| | - O Chdil
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
| | - M Balli
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
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Wan W, Guo R, Ge Y, Liu Y. Carrier and phonon transport in 2D InSe and its Janus structures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:133001. [PMID: 36634370 DOI: 10.1088/1361-648x/acb2a5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
Recently, two-dimensional (2D) Indium Selenide (InSe) has been receiving much attention in the scientific community due to its reduced size, extraordinary physical properties, and potential applications in various fields. In this review, we discussed the recent research advancement in the carrier and phonon transport properties of 2D InSe and its related Janus structures. We first introduced the progress in the synthesis of 2D InSe. We summarized the recent experimental and theoretical works on the carrier mobility, thermal conductivity, and thermoelectric characteristics of 2D InSe. Based on the Boltzmann transport equation (BTE), the mechanisms underlying carrier or phonon scattering of 2D InSe were discussed in detail. Moreover, the structural and transport properties of Janus structures based on InSe were also presented, with an emphasis on the theoretical simulations. At last, we discussed the prospects for continued research of 2D InSe.
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Affiliation(s)
- Wenhui Wan
- State Key Laboratory of Metastable Materials Science and Technology & Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Rui Guo
- State Key Laboratory of Metastable Materials Science and Technology & Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Yanfeng Ge
- State Key Laboratory of Metastable Materials Science and Technology & Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China
| | - Yong Liu
- State Key Laboratory of Metastable Materials Science and Technology & Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, People's Republic of China
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5
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Liu CJ, Wan Y, Li LJ, Lin CP, Hou TH, Huang ZY, Hu VPH. 2D Materials-Based Static Random-Access Memory. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107894. [PMID: 34932857 DOI: 10.1002/adma.202107894] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 12/14/2021] [Indexed: 06/14/2023]
Abstract
2D transition-metal dichalcogenide semiconductors, such as MoS2 and WSe2 , with adequate bandgaps are promising channel materials for ultrascaled logic transistors. This scalability study of 2D material (2DM)-based field-effect transistor (FET) and static random-access memory (SRAM) cells analyzing the impact of layer thickness reveals that the monolayer 2DM FET with superior electrostatics is beneficial for its ability to mitigate the read-write conflict in an SRAM cell at scaled technology nodes (1-2.1 nm). Moreover, the monolayer 2DM SRAM exhibits lower cell read access time and write time than the bilayer and trilayer 2DM SRAM cells at fixed leakage power. This simulation predicts that the optimization of 2DM SRAM designed with state-of-the-art contact resistance, mobility, and equivalent oxide thickness leads to excellent stability and operation speed at the 1-nm node. Applying the nanosheet (NS) gate-all-around (GAA) structure to 2DM further reduces cell read access time and write time and improves the area density of the SRAM cells, demonstrating a feasible scaling path beyond Si technology using 2DM NSFETs. In addition to the device design, the process challenges for 2DM NSFETs, including the cost-effective stacking of 2DM layers, formation of electrical contacts, suspended 2DM channels, and GAA structures, are also discussed.
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Affiliation(s)
- Chang-Ju Liu
- Department of Electrical Engineering, National Central University, Taoyuan, 320, Taiwan
| | - Yi Wan
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 9999077, Hong Kong
| | - Lain-Jong Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, 9999077, Hong Kong
| | - Chih-Pin Lin
- Department of Electrical Engineering and Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan
| | - Tuo-Hung Hou
- Department of Electrical Engineering and Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan
| | - Zi-Yuan Huang
- Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, 106, Taiwan
| | - Vita Pi-Ho Hu
- Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, 106, Taiwan
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6
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Wang Y, Gao Q, Li W, Cheng P, Zhang YQ, Feng B, Hu Z, Wu K, Chen L. Nearly Ideal Two-Dimensional Electron Gas Hosted by Multiple Quantized Kronig-Penney States Observed in Few-Layer InSe. ACS NANO 2022; 16:13014-13021. [PMID: 35943244 DOI: 10.1021/acsnano.2c05556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A theoretical ideal two-dimensional electron gas (2DEG) was characterized by a flat density of states independent of energy. Compared with conventional two-dimensional free-electron systems in semiconductor heterojunctions and noble metal surfaces, we report here the achievement of ideal 2DEG with multiple quantized states in few-layer InSe films. The multiple quantum well states (QWSs) in few-layer InSe films are found, and the number of QWSs is strictly equal to the number of atomic layers. The multiple stair-like DOS as well as multiple bands with parabolic dispersion both characterize ideal 2DEG features in these QWSs. Density functional theory calculations and numerical simulations based on quasi-bounded square potential wells described as the Kronig-Penney model provide a consistent explanation of 2DEG in the QWSs. Our work demonstrates that 2D van der Waals materials are ideal systems for realizing 2DEG hosted by multiple quantized Kronig-Penney states, and the semiconducting nature of the material provides a better chance for construction of high-performance electronic devices utilizing these states, for example, superlattice devices with negative differential resistance.
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Affiliation(s)
- Yu Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Qian Gao
- School of Physics, Nankai University, Tianjin 300071, China
| | - Wenhui Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Peng Cheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Yi-Qi Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Baojie Feng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhenpeng Hu
- School of Physics, Nankai University, Tianjin 300071, China
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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7
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He Y, Zhu YH, Zhang M, Du J, Guo WH, Liu SM, Tian C, Zhong HX, Wang X, Shi JJ. High hydrogen production in the InSe/MoSi 2N 4 van der Waals heterostructure for overall water splitting. Phys Chem Chem Phys 2022; 24:2110-2117. [PMID: 35019921 DOI: 10.1039/d1cp04705a] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Very recently, the septuple-atomic-layer MoSi2N4 has been successfully synthesized by a chemical vapor deposition method. However, pristine MoSi2N4 exhibits some shortcomings, including poor visible-light harvesting capability and a low separation rate of photo-excited electron-hole pairs, when it is applied in water splitting to produce hydrogen. Fortunately, we find that MoSi2N4 can be considered as a good co-catalyst to be stacked with InSe forming an efficient heterostructure photocatalyst. Here, the electronic and photocatalytic properties of the two-dimensional (2D) InSe/MoSi2N4 heterostructure have been systematically investigated by density functional theory for the first time. The results demonstrate that 2D InSe/MoSi2N4 has a type-II band alignment with a favourable direct bandgap of 1.61 eV and exhibits suitable band edge positions for overall water splitting. Particularly, 2D InSe/MoSi2N4 has high electron mobility (104 cm2 V-1 s-1) and shows a noticeable optical absorption coefficient (105 cm-1) in the visible-light region of the solar spectrum. These brilliant properties declare that 2D InSe/MoSi2N4 is a potential photocatalyst for overall water splitting.
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Affiliation(s)
- Yong He
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Yao-Hui Zhu
- Physics Department, Beijing Technology and Business University, Beijing 100048, China.
| | - Min Zhang
- Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, College of Physics and Electronic Information, Inner Mongolia Normal University, Hohhot 010022, China.
| | - Juan Du
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Wen-Hui Guo
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Shi-Ming Liu
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Chong Tian
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Hong-Xia Zhong
- School of Mathematics and Physics, China University of Geosciences, Wuhan 430074, China
| | - Xinqiang Wang
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
| | - Jun-Jie Shi
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University Yangtze Delta Institute of Optoelectronics, Peking University, Beijing 100871, China.
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8
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Xie Z, Chen L. Influence of Ce, Nd, Eu and Tm Dopants on the Properties of InSe Monolayer: A First-Principles Study. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2707. [PMID: 34685148 PMCID: PMC8541675 DOI: 10.3390/nano11102707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 11/16/2022]
Abstract
Doping of foreign atoms may substantially alter the properties of the host materials, in particular low-dimension materials, leading to many potential functional applications. Here, we perform density functional theory calculations of two-dimensional InSe materials with substitutional doping of lanthanide atoms (Ce, Nd, Eu, Tm) and investigate systematically their structural, magnetic, electronic and optical properties. The calculated formation energy shows that the substitutional doping of these lanthanide atoms is feasible in the InSe monolayer, and such doping is more favorable under Se-rich than In-rich conditions. As for the structure, doping of lanthanide atoms induces visible outward movement of the lanthanide atom and its surrounding Se atoms. The calculated total magnetic moments are 0.973, 2.948, 7.528 and 1.945 μB for the Ce-, Nd-, Eu-, and Tm-doped systems, respectively, which are mainly derived from lanthanide atoms. Further band structure calculations reveal that the Ce-doped InSe monolayer has n-type conductivity, while the Nd-doped InSe monolayer has p-type conductivity. The Eu- and Tm-doped systems are found to be diluted magnetic semiconductors. The calculated optical response of absorption in the four doping cases shows redshift to lower energy within the infrared range compared with the host InSe monolayer. These findings suggest that doping of lanthanide atoms may open up a new way of manipulating functionalities of InSe materials for low-dimension optoelectronics and spintronics applications.
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Affiliation(s)
- Zhi Xie
- College of Mechanical and Electronic Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
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Huang TX, Dong B, Filbrun SL, Okmi AA, Cheng X, Yang M, Mansour N, Lei S, Fang N. Single-molecule photocatalytic dynamics at individual defects in two-dimensional layered materials. SCIENCE ADVANCES 2021; 7:eabj4452. [PMID: 34597131 PMCID: PMC10938566 DOI: 10.1126/sciadv.abj4452] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
The insightful comprehension of in situ catalytic dynamics at individual structural defects of two-dimensional (2D) layered material, which is crucial for the design of high-performance catalysts via defect engineering, is still missing. Here, we resolved single-molecule trajectories resulted from photocatalytic activities at individual structural features (i.e., basal plane, edge, wrinkle, and vacancy) in 2D layered indium selenide (InSe) in situ to quantitatively reveal heterogeneous photocatalytic dynamics and surface diffusion behaviors. The highest catalytic activity was found at vacancy in a four-layer InSe, up to ~30× higher than that on the basal plane. Moreover, lower adsorption strength of reactant and slower dissociation/diffusion rates of product were found at more photocatalytic active defects. These distinct dynamic properties are determined by lattice structures/electronic energy levels of defects and layer thickness of supported InSe. Our findings shed light on the fundamental understanding of photocatalysis at defects and guide the rational defect engineering.
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Affiliation(s)
- Teng-Xiang Huang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Seth L. Filbrun
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Aisha Ahmad Okmi
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - Xiaodong Cheng
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
| | - Meek Yang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Nourhan Mansour
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Sidong Lei
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
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Zhang Z, Yuan Y, Zhou W, Chen C, Yuan S, Zeng H, Fu YS, Zhang W. Strain-Induced Bandgap Enhancement of InSe Ultrathin Films with Self-Formed Two-Dimensional Electron Gas. ACS NANO 2021; 15:10700-10709. [PMID: 34080842 DOI: 10.1021/acsnano.1c03724] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomically thin indium selenide (InSe) is a representative two-dimensional (2D) family that have recently attracted extensive interest for their intriguing emerging physics and potential optoelectronic applications with high-performance. Here, by utilizing molecular beam epitaxy and scanning tunneling microscopy, we report a controlled synthesis of InSe thin films down to the monolayer limit and characterization of their electronic properties at atomic scale. Highly versatile growth conditions are developed to fabricate well crystalline InSe films, with a reversible and controllable phase transformation between InSe and In2Se3. The band gap size of InSe films, as enhanced by quantum confinement, increases with decreasing film thickness. Near various categories of lattice imperfections, the band gap becomes significantly enlarged, resulting in a type-I band alignments for lateral heterojunctions. Such band gap enhancement, as unveiled from our first-principles calculations, is ascribed to the local compressive strain imposed by the lattice imperfections. Moreover, InSe films host highly conductive 2D electron gas, manifesting prominent quasiparticle scattering signatures. The 2D electron gas is self-formed via substrate doping of electrons, which shift the Fermi level above the confinement-quantized conduction band. Our study identifies InSe ultrathin film as an appealing system for both fundamental research and potential applications in nanoelectrics and optoelectronics.
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Affiliation(s)
- Zhimo Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuan Yuan
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Weiqing Zhou
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Chen Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shengjun Yuan
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hualing Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ying-Shuang Fu
- 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
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Ahmad I, Shahid I, Ali A, Gao L, Cai J. Electronic, mechanical, optical and photocatalytic properties of two-dimensional Janus XGaInY (X, Y ;= S, Se and Te) monolayers. RSC Adv 2021; 11:17230-17239. [PMID: 35479691 PMCID: PMC9033172 DOI: 10.1039/d1ra02324a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 04/26/2021] [Indexed: 11/21/2022] Open
Abstract
Janus monolayers with breaking out-of-plane structural symmetries and spontaneous electric polarizations offer new possibilities in the field of two-dimensional materials. Due to the depletion of fossil fuels and serious environmental problems, there has been a growing interest in the conversion of water and solar energy into H2 fuels in recent years. In this research, Janus XGaInY (X, Y = S, Se and Te) monolayers are predicted as promising solar-water-splitting photocatalysts. Based on first-principles calculations, the electronic, mechanical, optical and photocatalytic properties of Janus XGaInY (X, Y = S, Se and Te) monolayers are investigated. These Janus monolayers are structurally stable semiconductors with indirect bandgaps, except for SGaInSe, SGaInTe, TeGaInS and SeGaInTe. Their energy bandgaps extend from 0.74 to 2.66 eV at a hybrid density functional level, which is crucial for broadband photoresponses. Moreover, these Janus monolayers not only show strong light absorption coefficients greater than 104 cm−1 in the visible and ultraviolet regions but possess suitable band edge positions for water splitting. Our findings reveal that these Janus monolayers have a potential for application in the fields of optoelectronic and photocatalysis. Janus monolayers with breaking out-of-plane structural symmetries and spontaneous electric polarizations offer new possibilities in the field of two-dimensional materials.![]()
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Affiliation(s)
- Iqtidar Ahmad
- School of Material Science and Engineering, Kunming University of Science and Technology Kunming 650093 Yunnan P. R. China
| | - Ismail Shahid
- School of Materials Science and Engineering, Computational Centre for Molecular Science, Institute of New Energy Material Chemistry, Nankai University Tianjin 300350 P. R. China
| | - Anwar Ali
- College of Physics and Information Technology, Shaanxi Normal University Xian 710119 Shaanxi P. R. China
| | - Lei Gao
- Faculty of Science, Kunming University of Science and Technology Kunming 650093 Yunnan P. R. China
| | - Jinming Cai
- School of Material Science and Engineering, Kunming University of Science and Technology Kunming 650093 Yunnan P. R. China
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Chen F, Cui A, Wang X, Gao C, Xu L, Jiang K, Zhang J, Hu Z, Chu J. Lattice vibration characteristics in layered InSe films and the electronic behavior of field-effect transistors. NANOTECHNOLOGY 2020; 31:335702. [PMID: 32344392 DOI: 10.1088/1361-6528/ab8df1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding how temperature affects the structural and electronic properties for two-dimensional (2D) semiconductors could promote the application and development of nanoelectronic devices. Here, the temperature dependence of lattice structure for indium selenide (InSe) nanosheets and the corresponding electronic properties of 3 nm indium-deposited InSe field-effect transistors (FETs) are systematically demonstrated. Analyses of Raman spectra suggest that the difference of phonon frequency (Δω) for the A[Formula: see text] mode is found to be 3.14 cm-1, which is larger than that of the E[Formula: see text] mode due to the stronger electron-phonon coupling for the A[Formula: see text] mode. The device performance based on indium-deposited InSe is systematically explained using Kelvin probe force microscopy (KPFM) and the predicted energy band structure. Furthermore, FETs based on temperature and variable thickness InSe flakes are designed as applicable devices. Our findings are of fundamental importance to explain the underlying physics in intrinsic InSe transistors and improve further applications.
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Affiliation(s)
- Fangfang Chen
- Technical Center for Multifunctional Magneto-Optical Spectroscopy (Shanghai), Engineering Research Center of Nanophotonics Advanced Instrument (Ministry of Education), Department of Materials, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, People's Republic of China
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13
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Sun Y, Li Y, Li T, Biswas K, Patanè A, Zhang L. New Polymorphs of 2D Indium Selenide with Enhanced Electronic Properties. ADVANCED FUNCTIONAL MATERIALS 2020; 30:2001920. [PMID: 32774197 PMCID: PMC7405953 DOI: 10.1002/adfm.202001920] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 05/05/2023]
Abstract
The 2D semiconductor indium selenide (InSe) has attracted significant interest due its unique electronic band structure, high electron mobility, and wide tunability of its band gap energy achieved by varying the layer thickness. All these features make 2D InSe a potential candidate for advanced electronic and optoelectronic applications. Here, the discovery of new polymorphs of InSe with enhanced electronic properties is reported. Using a global structure search that combines artificial swarm intelligence with first-principles energetic calculations, polymorphs that consist of a centrosymmetric monolayer belonging to the point group D 3d are identified, distinct from well-known polymorphs based on the D 3h monolayers that lack inversion symmetry. The new polymorphs are thermodynamically and kinetically stable, and exhibit a wider optical spectral response and larger electron mobilities compared to the known polymorphs. Opportunities to synthesize these newly discovered polymorphs and viable routes to identify them by X-ray diffraction, Raman spectroscopy, and second harmonic generation experiments are discussed.
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Affiliation(s)
- Yuanhui Sun
- State Key Laboratory of Integrated OptoelectronicsKey Laboratory of Automobile Materials of MOE and College of Materials Science and EngineeringJilin UniversityChangchun130012China
| | - Yawen Li
- State Key Laboratory of Integrated OptoelectronicsKey Laboratory of Automobile Materials of MOE and College of Materials Science and EngineeringJilin UniversityChangchun130012China
| | - Tianshu Li
- State Key Laboratory of Integrated OptoelectronicsKey Laboratory of Automobile Materials of MOE and College of Materials Science and EngineeringJilin UniversityChangchun130012China
| | - Koushik Biswas
- Department of Chemistry and PhysicsArkansas State UniversityJonesboroAR72467USA
| | - Amalia Patanè
- School of Physics and AstronomyThe University of NottinghamNottinghamNG7 2RDUK
| | - Lijun Zhang
- State Key Laboratory of Integrated OptoelectronicsKey Laboratory of Automobile Materials of MOE and College of Materials Science and EngineeringJilin UniversityChangchun130012China
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14
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Ding YM, Nie X, Dong H, Rujisamphan N, Li Y. Many-body effects in an MXene Ti 2CO 2 monolayer modified by tensile strain: GW-BSE calculations. NANOSCALE ADVANCES 2020; 2:2471-2477. [PMID: 36133373 PMCID: PMC9417291 DOI: 10.1039/c9na00632j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 05/05/2020] [Indexed: 06/01/2023]
Abstract
MXenes, two-dimensional (2D) layered transition metal carbide/nitride materials with a lot of advantages including high carrier mobility, tunable band gap, favorable mechanical properties and excellent structural stability, have attracted research interest worldwide. It is imperative to accurately understand their electronic and optical properties. Here, the electronic and optical response properties of a Ti2CO2 monolayer, a typical member of MXenes, are investigated on the basis of first-principles calculations including many-body effects. Our results show that the pristine Ti2CO2 monolayer displays an indirect quasi-particle (QP) band gap of 1.32 eV with the conduction band minimum (CBM) located at the M point and valence band maximum (VBM) located at the Γ point. The optical band gap and binding energy of the first bright exciton are calculated to be 1.26 eV and 0.56 eV, respectively. Under biaxial tensile strains, the lowest unoccupied band at the Γ point shifts downward, while the lowest unoccupied band at the M point shifts upward. Then, a direct band gap appears at the Γ point in 6%-strained Ti2CO2. Moreover, the optical band gap and binding energy of the first bright exciton decrease continuously with the increase of the strain due to the increase of the lattice parameter and the expansion of the exciton wave function. More importantly, the absorbed photon flux of Ti2CO2 is calculated to be 1.76-1.67 mA cm-2 with the variation of the strain, suggesting good sunlight optical absorbance. Our work demonstrates that Ti2CO2, as well as other MXenes, hold untapped potential for photo-detection and photovoltaic applications.
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Affiliation(s)
- Yi-Min Ding
- Institute of Functional Nano & Solf Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou Jiangsu 215123 China
| | - Xiaomin Nie
- Institute of Functional Nano & Solf Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou Jiangsu 215123 China
| | - Huilong Dong
- School of Chemistry and Materials Engineering, Changshu Institute of Technology Changshu Jiangsu 215500 China
| | - Nopporn Rujisamphan
- King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Road, Bang Mod, Thung Khru Bangkok 10140 Thailand
| | - Youyong Li
- Institute of Functional Nano & Solf Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou Jiangsu 215123 China
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15
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Xu L, Liu S, Zhang H, Zhang X, Li J, Yan J, Shi B, Yang J, Yang C, Xu L, Sun X, Lu J. First-principles simulation of monolayer hydrogen passivated Bi2O2S2–metal interfaces. Phys Chem Chem Phys 2020; 22:7853-7863. [DOI: 10.1039/d0cp00058b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lateral SBH and Fermi level change in the hydrogen-passivated Bi2O2S2 FET.
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16
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Somaiya RN, Sonvane YA, Gupta SK. Exploration of the strain and thermoelectric properties of hexagonal SiX (X = N, P, As, Sb, and Bi) monolayers. Phys Chem Chem Phys 2020; 22:3990-3998. [DOI: 10.1039/d0cp00002g] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Si based group V binary compounds have shown better thermoelectric performance at room temperature in addition with ultrahigh carrier mobilities.
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Affiliation(s)
- Radha N Somaiya
- Advanced Materials Lab
- Department of Applied Physics
- S.V. National Institute of Technology
- Surat 395007
- India
| | - Yogesh Ashokbhai Sonvane
- Advanced Materials Lab
- Department of Applied Physics
- S.V. National Institute of Technology
- Surat 395007
- India
| | - Sanjeev K. Gupta
- Computational Materials and Nanoscience Group
- Department of Physics
- St Xavier's College
- Ahmedabad 380009
- India
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17
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Du J, Shi JJ. 2D Ca 3 Sn 2 S 7 Chalcogenide Perovskite: A Graphene-Like Semiconductor with Direct Bandgap 0.5 eV and Ultrahigh Carrier Mobility 6.7 × 10 4 cm 2 V -1 s -1. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1905643. [PMID: 31682038 DOI: 10.1002/adma.201905643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/14/2019] [Indexed: 05/17/2023]
Abstract
Graphene, a star 2D material, has attracted much attention because of its unique properties including linear electronic dispersion, massless carriers, and ultrahigh carrier mobility (104 -105 cm2 V-1 s-1 ). However, its zero bandgap greatly impedes its application in the semiconductor industry. Opening the zero bandgap has become an unresolved worldwide problem. Here, a novel and stable 2D Ruddlesden-Popper-type layered chalcogenide perovskite semiconductor Ca3 Sn2 S7 is found based on first-principles GW calculations, which exhibits excellent electronic, optical, and transport properties, as well as soft and isotropic mechanical characteristics. Surprisingly, it has a graphene-like linear electronic dispersion, small carrier effective mass (0.04 m0 ), ultrahigh room-temperature carrier mobility (6.7 × 104 cm2 V-1 s-1 ), Fermi velocity (3 × 105 m s-1 ), and optical absorption coefficient (105 cm-1 ). Particularly, it has a direct quasi-particle bandgap of 0.5 eV, which realizes the dream of opening the graphene bandgap in a new way. These results guarantee its application in infrared optoelectronic and high-speed electronic devices.
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Affiliation(s)
- Juan Du
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, China
| | - Jun-Jie Shi
- State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, China
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18
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Qi L, Gao W, Jiang Q. Strain engineering of the electronic and transport properties of monolayer tellurenyne. Phys Chem Chem Phys 2019; 21:23119-23128. [PMID: 31608349 DOI: 10.1039/c9cp03547h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) materials exhibiting quality electronic properties such as suitable band gap, giant Rashba effect and high carrier mobility are essential for promising applications in electronics and spintronics. Strain engineering has been recognized as an effective strategy to engineer the atomic and electronic properties of 2D materials. Herein, based on density functional theory, we demonstrate that the electronic properties of tellurenyne can be tuned well by using uniaxial strain. We find that tellurenyne retains the unique noncovalent bond structure and exhibits good stability under the uniaxial strain. Meanwhile, the band gap of tellurenyne can be tuned to a large scale (0.33-1.18 eV and 0.73-1.27 eV under the uniaxial strain along and perpendicular to the chain direction, respectively). Under 10% tension strain along the chain direction, the Rashba constant reaches 2.96 eV Å, belonging to giant Rashba systems. More importantly, the hole mobility of tellurenyne along the chain direction reaches 1.1 × 105 cm2 V-1 s-1 under 10% tension strain along the chain direction, which is one order of magnitude larger than that of phosphorene. Therefore, these remarkable electronic properties of tellurenyne engineered by using strain indicate its potential applications in electronics and spintronics.
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Affiliation(s)
- Liujian Qi
- Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering, Jilin University, 130022, Changchun, China.
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19
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Optimized band gap and fast interlayer charge transfer in two-dimensional perovskite oxynitride Ba2NbO3N and Sr2NbO3/Ba2NbO3N bonded heterostructure visible-light photocatalysts for overall water splitting. J Colloid Interface Sci 2019; 546:20-31. [DOI: 10.1016/j.jcis.2019.03.044] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/28/2019] [Accepted: 03/13/2019] [Indexed: 11/22/2022]
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20
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Zhang Z, Zhang Y, Xie Z, Wei X, Guo T, Fan J, Ni L, Tian Y, Liu J, Duan L. Tunable electronic properties of an Sb/InSe van der Waals heterostructure by electric field effects. Phys Chem Chem Phys 2019; 21:5627-5633. [DOI: 10.1039/c8cp07407k] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An Sb/InSe heterostructure manifests a varied direct bandgap under an electric field which is more favorable to FETs and MEMS devices.
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Affiliation(s)
- Zhihui Zhang
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Yan Zhang
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Zifeng Xie
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Xing Wei
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Tingting Guo
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Jibin Fan
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Lei Ni
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
| | - Ye Tian
- Institute of Physics
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Jian Liu
- School of Physics
- Shandong University
- Jinan 250100
- China
| | - Li Duan
- School of Materials Science and Engineering
- Chang’an University
- Xi’an
- China
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21
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Shi B, Wang Y, Li J, Zhang X, Yan J, Liu S, Yang J, Pan Y, Zhang H, Yang J, Pan F, Lu J. n-Type Ohmic contact and p-type Schottky contact of monolayer InSe transistors. Phys Chem Chem Phys 2018; 20:24641-24651. [DOI: 10.1039/c8cp04615h] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We explore the contact properties of monolayer InSe transistors and obtain n-type Ohmic/p-type Schottky contacts.
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