1
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Shcherbakov D, Voigt G, Memaran S, Liu GB, Wang Q, Watanabe K, Taniguchi T, Smirnov D, Balicas L, Zhang F, Lau CN. Giant Tunability of Intersubband Transitions and Quantum Hall Quartets in Few-Layer InSe Quantum Wells. NANO LETTERS 2024; 24:3851-3857. [PMID: 38502010 DOI: 10.1021/acs.nanolett.3c04121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
A two-dimensional (2D) quantum electron system is characterized by quantized energy levels, or subbands, in the out-of-plane direction. Populating higher subbands and controlling the intersubband transitions have wide technological applications such as optical modulators and quantum cascade lasers. In conventional materials, however, the tunability of intersubband spacing is limited. Here we demonstrate electrostatic population and characterization of the second subband in few-layer InSe quantum wells, with giant tunability of its energy, population, and spin-orbit coupling strength, via the control of not only layer thickness but also the out-of-plane displacement field. A modulation of as much as 350% or over 250 meV is achievable, underscoring the promise of InSe for tunable infrared and THz sources, detectors, and modulators.
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Affiliation(s)
- Dmitry Shcherbakov
- Department of Physics, The Ohio State University, Columbus, Ohio 43221, United States
| | - Greyson Voigt
- Department of Physics, The Ohio State University, Columbus, Ohio 43221, United States
| | - Shahriar Memaran
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Gui-Bin Liu
- School of Physics, Beijing Institute of Technology, 100081 Beijing, China
| | - Qiyue Wang
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Luis Balicas
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Fan Zhang
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Chun Ning Lau
- Department of Physics, The Ohio State University, Columbus, Ohio 43221, United States
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2
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Shiffa M, Dewes BT, Bradford J, Cottam ND, Cheng TS, Mellor CJ, Makarovskiy O, Rahman K, O'Shea JN, Beton PH, Novikov SV, Ben T, Gonzalez D, Xie J, Zhang L, Patanè A. Wafer-Scale Two-Dimensional Semiconductors for Deep UV Sensing. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305865. [PMID: 37798672 DOI: 10.1002/smll.202305865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/29/2023] [Indexed: 10/07/2023]
Abstract
2D semiconductors (2SEM) can transform many sectors, from information and communication technology to healthcare. To date, top-down approaches to their fabrication, such as exfoliation of bulk crystals by "scotch-tape," are widely used, but have limited prospects for precise engineering of functionalities and scalability. Here, a bottom-up technique based on epitaxy is used to demonstrate high-quality, wafer-scale 2SEM based on the wide band gap gallium selenide (GaSe) compound. GaSe layers of well-defined thickness are developed using a bespoke facility for the epitaxial growth and in situ studies of 2SEM. The dominant centrosymmetry and stacking of the individual van der Waals layers are verified by theory and experiment; their optical anisotropy and resonant absorption in the UV spectrum are exploited for photon sensing in the technological UV-C spectral range, offering a scalable route to deep-UV optoelectronics.
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Affiliation(s)
- Mustaqeem Shiffa
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Benjamin T Dewes
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Jonathan Bradford
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Nathan D Cottam
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Tin S Cheng
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Christopher J Mellor
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Oleg Makarovskiy
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Kazi Rahman
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - James N O'Shea
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Peter H Beton
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sergei V Novikov
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Teresa Ben
- University Research Institute on Electron Microscopy and Materials, IMEYMAT, Universidad de Cádiz, Cádiz, 11510, Spain
| | - David Gonzalez
- University Research Institute on Electron Microscopy and Materials, IMEYMAT, Universidad de Cádiz, Cádiz, 11510, Spain
| | - Jiahao Xie
- College of Materials Science and Engineering, Jilin University, Changchun, 130012, China
| | - Lijun Zhang
- College of Materials Science and Engineering, Jilin University, Changchun, 130012, China
| | - Amalia Patanè
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
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3
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Ghosh S, Zhang J, Wasala M, Patil P, Pradhan N, Talapatra S. Probing the Electronic and Opto-Electronic Properties of Multilayer MoS 2 Field-Effect Transistors at Low Temperatures. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2333. [PMID: 37630917 PMCID: PMC10459643 DOI: 10.3390/nano13162333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/18/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023]
Abstract
Transition metal dichalcogenides (TMDs)-based field-effect transistors (FETs) are being investigated vigorously for their promising applications in optoelectronics. Despite the high optical response reported in the literature, most of them are studied at room temperature. To extend the application of these materials in a photodetector, particularly at a low temperature, detailed understanding of the photo response behavior of these materials at low temperatures is crucial. Here we present a systematic investigation of temperature-dependent electronic and optoelectronic properties of few-layers MoS2 FETs, synthesized using the mechanical exfoliation of bulk MoS2 crystal, on the Si/SiO2 substrate. Our MoS2 FET show a room-temperature field-effect mobility μFE ~40 cm2·V-1·s-1, which increases with decreasing temperature, stabilizing at 80 cm2·V-1·s-1 below 100 K. The temperature-dependent (50 K < T < 300 K) photoconductivity measurements were investigated using a continuous laser source λ = 658 nm (E = 1.88 eV) over a broad range of effective illuminating laser intensity, Peff (0.02 μW < Peff < 0.6 μW). Photoconductivity measurements indicate a fractional power dependence of the steady-state photocurrent. The room-temperature photoresponsivity (R) obtained in these samples was found to be ~2 AW-1, and it increases as a function of decreasing temperature, reaching a maximum at T = 75 K. The optoelectronic properties of MoS2 at a low temperature give an insight into photocurrent generation mechanisms, which will help in altering/improving the performance of TMD-based devices for various applications.
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Affiliation(s)
- Sujoy Ghosh
- School of Physics and Applied Physics, Southern Illinois University, Carbondale, IL 62901, USA; (S.G.); (M.W.); (P.P.)
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Jie Zhang
- School of Physics and Applied Physics, Southern Illinois University, Carbondale, IL 62901, USA; (S.G.); (M.W.); (P.P.)
| | - Milinda Wasala
- School of Physics and Applied Physics, Southern Illinois University, Carbondale, IL 62901, USA; (S.G.); (M.W.); (P.P.)
| | - Prasanna Patil
- School of Physics and Applied Physics, Southern Illinois University, Carbondale, IL 62901, USA; (S.G.); (M.W.); (P.P.)
| | - Nihar Pradhan
- Department of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, MS 39217, USA;
| | - Saikat Talapatra
- School of Physics and Applied Physics, Southern Illinois University, Carbondale, IL 62901, USA; (S.G.); (M.W.); (P.P.)
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4
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Montblanch ARP, Barbone M, Aharonovich I, Atatüre M, Ferrari AC. Layered materials as a platform for quantum technologies. NATURE NANOTECHNOLOGY 2023:10.1038/s41565-023-01354-x. [PMID: 37322143 DOI: 10.1038/s41565-023-01354-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 02/17/2023] [Indexed: 06/17/2023]
Abstract
Layered materials are taking centre stage in the ever-increasing research effort to develop material platforms for quantum technologies. We are at the dawn of the era of layered quantum materials. Their optical, electronic, magnetic, thermal and mechanical properties make them attractive for most aspects of this global pursuit. Layered materials have already shown potential as scalable components, including quantum light sources, photon detectors and nanoscale sensors, and have enabled research of new phases of matter within the broader field of quantum simulations. In this Review we discuss opportunities and challenges faced by layered materials within the landscape of material platforms for quantum technologies. In particular, we focus on applications that rely on light-matter interfaces.
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Affiliation(s)
- Alejandro R-P Montblanch
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Matteo Barbone
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK
- Munich Center for Quantum Science and Technology, (MCQST), Munich, Germany
- Walter Schottky Institut and Department of Electrical and Computer Engineering, Technische Universität München, Garching, Germany
| | - Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
- Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
| | - Mete Atatüre
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK.
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5
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Bao X, Wu X, Ke Y, Wu K, Jiang C, Wu B, Li J, Yue S, Zhang S, Shi J, Du W, Zhong Y, Hu H, Bai P, Gong Y, Zhang Q, Zhang W, Liu X. Giant Out-of-Plane Exciton Emission Enhancement in Two-Dimensional Indium Selenide via a Plasmonic Nanocavity. NANO LETTERS 2023; 23:3716-3723. [PMID: 37125916 DOI: 10.1021/acs.nanolett.2c04902] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Out-of-plane (OP) exciton-based emitters in two-dimensional semiconductor materials are attractive candidates for novel photonic applications, such as radially polarized sources, integrated photonic chips, and quantum communications. However, their low quantum efficiency resulting from forbidden transitions limits their practicality. In this work, we achieve a giant enhancement of up to 34000 for OP exciton emission in indium selenide (InSe) via a designed Ag nanocube-over-Au film plasmonic nanocavity. The large photoluminescence enhancement factor (PLEF) is attributed to the induced OP local electric field (Ez) within the nanocavity, which facilitates effective OP exciton-plasmon interaction and subsequent tremendous enhancement. Moreover, the nanoantenna effect resulting from the effective interaction improves the directivity of spontaneous radiation. Our results not only reveal an effective photoluminescence enhancement approach for OP excitons but also present an avenue for designing on-chip photonic devices with an OP dipole orientation.
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Affiliation(s)
- Xiaotian Bao
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, People's Republic of China
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Xianxin Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuxuan Ke
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Keming Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Chuanxiu Jiang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bo Wu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Jing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shuai Yue
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Shuai Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jianwei Shi
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wenna Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yangguang Zhong
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Huatian Hu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, People's Republic of China
| | - Peng Bai
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yiyang Gong
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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6
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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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7
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Cull W, Skowron ST, Hayter R, Stoppiello CT, Rance GA, Biskupek J, Kudrynskyi ZR, Kovalyuk ZD, Allen CS, Slater TJA, Kaiser U, Patanè A, Khlobystov AN. Subnanometer-Wide Indium Selenide Nanoribbons. ACS NANO 2023; 17:6062-6072. [PMID: 36916820 PMCID: PMC10061931 DOI: 10.1021/acsnano.3c00670] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
Indium selenides (InxSey) have been shown to retain several desirable properties, such as ferroelectricity, tunable photoluminescence through temperature-controlled phase changes, and high electron mobility when confined to two dimensions (2D). In this work we synthesize single-layer, ultrathin, subnanometer-wide InxSey by templated growth inside single-walled carbon nanotubes (SWCNTs). Despite the complex polymorphism of InxSey we show that the phase of the encapsulated material can be identified through comparison of experimental aberration-corrected transmission electron microscopy (AC-TEM) images and AC-TEM simulations of known structures of InxSey. We show that, by altering synthesis conditions, one of two different stoichiometries of sub-nm InxSey, namely InSe or β-In2Se3, can be prepared. Additionally, in situ AC-TEM heating experiments reveal that encapsulated β-In2Se3 undergoes a phase change to γ-In2Se3 above 400 °C. Further analysis of the encapsulated species is performed using X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX), and Raman spectroscopy, corroborating the identities of the encapsulated species. These materials could provide a platform for ultrathin, subnanometer-wide phase-change nanoribbons with applications as nanoelectronic components.
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Affiliation(s)
- William
J. Cull
- School
of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Stephen T. Skowron
- School
of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Ruth Hayter
- School
of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Craig T. Stoppiello
- Nanoscale
and Microscale Research Centre, University
of Nottingham, Nottingham NG7 2QL, United Kingdom
| | - Graham A. Rance
- Nanoscale
and Microscale Research Centre, University
of Nottingham, Nottingham NG7 2QL, United Kingdom
| | - Johannes Biskupek
- Central
Facility of Electron Microscopy, Electron Microscopy Group of Materials
Science, University of Ulm, 89081 Ulm, Germany
| | - Zakhar R. Kudrynskyi
- School
of Physics, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Faculty
of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Zakhar D. Kovalyuk
- Institute
for Problems of Materials Science, National Academy of Sciences of
Ukraine, Chernivtsi Branch, 58001 Chernivtsi, Ukraine
| | - Christopher S. Allen
- Electron
Physical Sciences Imaging Centre, Diamond
Light Source ltd, Didcot OX11 0DE, United Kingdom
| | - Thomas J. A. Slater
- Electron
Physical Sciences Imaging Centre, Diamond
Light Source ltd, Didcot OX11 0DE, United Kingdom
| | - Ute Kaiser
- Central
Facility of Electron Microscopy, Electron Microscopy Group of Materials
Science, University of Ulm, 89081 Ulm, Germany
| | - Amalia Patanè
- School
of Physics, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Andrei N. Khlobystov
- School
of Chemistry, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
- Nanoscale
and Microscale Research Centre, University
of Nottingham, Nottingham NG7 2QL, United Kingdom
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8
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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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9
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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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10
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Li N, Okmi A, Jabegu T, Zheng H, Chen K, Lomashvili A, Williams W, Maraba D, Kravchenko I, Xiao K, He K, Lei S. van der Waals Semiconductor Empowered Vertical Color Sensor. ACS NANO 2022; 16:8619-8629. [PMID: 35436098 DOI: 10.1021/acsnano.1c09875] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Biomimetic artificial vision is receiving significant attention nowadays, particularly for the development of neuromorphic electronic devices, artificial intelligence, and microrobotics. Nevertheless, color recognition, the most critical vision function, is missed in the current research due to the difficulty of downscaling of the prevailing color sensing devices. Conventional color sensors typically adopt a lateral color sensing channel layout and consume a large amount of physical space, whereas compact designs suffer from an unsatisfactory color detection accuracy. In this work, we report a van der Waals semiconductor-empowered vertical color sensing structure with the emphasis on compact device profile and precise color recognition capability. More attractive, we endow color sensor hardware with the function of chromatic aberration correction, which can simplify the design of an optical lens system and, in turn, further downscales the artificial vision systems. Also, the dimension of a multiple pixel prototype device in our study confirms the scalability and practical potentials of our developed device architecture toward the above applications.
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Affiliation(s)
- Ningxin Li
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
| | - Aisha Okmi
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
- Department of Physics, Jazan University, Jazan 45142, Saudi Arabia
| | - Tara Jabegu
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
| | - Hongkui Zheng
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Kuangcai Chen
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303, United States
| | - Alexander Lomashvili
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
| | - Westley Williams
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
| | - Diren Maraba
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
| | - Ivan Kravchenko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Kai Xiao
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Kai He
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
- Department of Material Science and Engineering, University of California, Irvine, California 92697, United States
| | - Sidong Lei
- Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, United States
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11
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Nur R, Tsuchiya T, Toprasertpong K, Terabe K, Takagi S, Takenaka M. A floating gate negative capacitance MoS 2 phototransistor with high photosensitivity. NANOSCALE 2022; 14:2013-2022. [PMID: 35072675 DOI: 10.1039/d1nr06315d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Monolayer MoS2 exhibits interesting optoelectronic properties that have been utilized in applications such as photodetectors and light emitting diodes. For image sensing applications, improving the light sensitivity relies on achieving a low dark current that enables the detection weak light signals. Although previous reports on improving the detectivity have been explored with heterostructures and pn junction devices, some of these approaches lack CMOS compatibility processing and sufficient low dark current suppression. Steep slope transistors that overcome the Boltzmann tyranny can further enhance the performance in photodetectors by providing efficient extraction of photogenerated charges. Here, we report a monolayer MoS2 floating gate negative capacitance phototransistor with the integration of a hafnium-zirconium oxide ferroelectric capacitor. In this study, a SSmin of 30 mV dec-1, very low dark currents of 10-13-10-14 A, and a high detectivity of 7.2 × 1015 cm Hz1/2 W-1 were achieved under weak light illumination due to an enhancement in the photogating effect. In addition, its potential as an optical memory and as an optical synapse with excellent long-term potentiation characteristics in an artificial neural network was also explored. Overall, this device structure offers high photosensitivity to weak light signals for future low-powered optoelectronic applications.
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Affiliation(s)
- Roda Nur
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Takashi Tsuchiya
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Kasidit Toprasertpong
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Kazuya Terabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science (NIMS), 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Shinichi Takagi
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Mitsuru Takenaka
- Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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12
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Zhang Z, Nie J, Zhang Z, Yuan Y, Fu YS, Zhang W. Atomic Visualization and Switching of Ferroelectric Order in β-In 2 Se 3 Films at the Single Layer Limit. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106951. [PMID: 34755394 DOI: 10.1002/adma.202106951] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/24/2021] [Indexed: 06/13/2023]
Abstract
2D ferroelectrics have received wide interest due to the remarkable quantum states of emerging physics at reduced dimensionality, associated with their exotic properties in high-performance and nonvolatile functional devices. Here, by combing molecular beam epitaxy synthesis and scanning tunneling microscopy characterization, two metastable phases of layered In2 Se3 films: β'- and β*-In2 Se3 are reported, which develop different types of in-plane spontaneous polarizations, thus resulting in different striped morphologies. The anti-ferroelectric order in β'-In2 Se3 and ferroelectric order of β*-In2 Se3 are identified, respectively, down to the 2D limit by comprehensive investigations of structural and spectroscopic signatures, including the lattice distortion, the spatial profile of images, the formation of domain structure, and the electronic band-bending by polarization charges at edges. The ferroelectric switching between those two phases are further controlled via applying an electric field generated from the scanning tunneling microscopy tip in a reversible manner. The intriguing tunability between the (anti-)ferroelectric orders in the 2D limit provides a promising platform for studying the interplay between electronic structure and ferroelectricity in van der Waals materials, and promotes potential development of miniaturized transistors and memory devices based on electric polarizations.
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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
| | - Jinhua Nie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhihao 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
| | - 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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13
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Zhu W, Lin H, Yan F, Hu C, Wang Z, Zhao L, Deng Y, Kudrynskyi ZR, Zhou T, Kovalyuk ZD, Zheng Y, Patanè A, Žutić I, Li S, Zheng H, Wang K. Large Tunneling Magnetoresistance in van der Waals Ferromagnet/Semiconductor Heterojunctions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2104658. [PMID: 34642998 DOI: 10.1002/adma.202104658] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/01/2021] [Indexed: 06/13/2023]
Abstract
2D layered chalcogenide semiconductors have been proposed as a promising class of materials for low-dimensional electronic, optoelectronic, and spintronic devices. Here, all-2D van der Waals vertical spin-valve devices, that combine the 2D layered semiconductor InSe as a spacer with the 2D layered ferromagnetic metal Fe3 GeTe2 as spin injection and detection electrodes, are reported. Two distinct transport behaviors are observed: tunneling and metallic, which are assigned to the formation of a pinhole-free tunnel barrier at the Fe3 GeTe2 /InSe interface and pinholes in the InSe spacer layer, respectively. For the tunneling device, a large magnetoresistance (MR) of 41% is obtained under an applied bias current of 0.1 µA at 10 K, which is about three times larger than that of the metallic device. Moreover, the tunneling device exhibits a lower operating bias current but a more sensitive bias current dependence than the metallic device. The MR and spin polarization of both the metallic and tunneling devices decrease with increasing temperature, which can be fitted well by Bloch's law. These findings reveal the critical role of pinholes in the MR of all-2D van der Waals ferromagnet/semiconductor heterojunction devices.
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Affiliation(s)
- Wenkai Zhu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hailong Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Faguang Yan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Ce Hu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ziao Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lixia Zhao
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Tiangong University, Tianjin, 300387, China
| | - Yongcheng Deng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zakhar R Kudrynskyi
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Tong Zhou
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Zakhar D Kovalyuk
- Frantsevich Institute for Problems of Materials Science, The National Academy of Sciences of Ukraine, Chernivtsi Branch, Chernivtsi, 58001, Ukraine
| | - Yuanhui Zheng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
| | - Amalia Patanè
- School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Igor Žutić
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Shushen Li
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Houzhi Zheng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kaiyou Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, China
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14
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Lee JH, Song J, Shin DH, Park S, Kim HR, Cho SP, Hong BH. Gradual Edge Contact between Mo and MoS 2 Formed by Graphene-Masked Sulfurization for High-Performance Field-Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2021; 13:54536-54542. [PMID: 34730950 DOI: 10.1021/acsami.1c15648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional materials have attracted great attention for their outstanding electronic properties. In particular, molybdenum disulfide (MoS2) shows great potential as a next-generation semiconductor due to its tunable direct bandgap with a high on-off ratio and extraordinary stability. However, the performance of MoS2 synthesized by physical vapor deposition has been limited by contact resistance between an electrode and MoS2, which determines overall device characteristics. Here, in order to reduce the contact resistance, we use in situ sulfurization of Mo by H2S gas treatment masked by a patterned graphene gas barrier, so that the Mo channel area can be selectively formed, resulting in a gradual edge contact between Mo and MoS2. Compared with field-effect transistors with a top contact between the Au/Ti electrode and the MoS2 channel, a gradual edge contact between the Mo electrode and the MoS2 channel provides a considerably enhanced electrical performance.
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Affiliation(s)
- Jong-Hwan Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
| | - Jaekwang Song
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
| | - Dong Heon Shin
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
| | - Seoungwoong Park
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
| | - Hwa Rang Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
| | - Sung-Pyo Cho
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
- National Center for Inter-University Research Facilities, Seoul National University, Seoul 08826, Korea
| | - Byung Hee Hong
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
- Graphene Research Center, Advanced Institute of Convergence Technology, Suwon 16229, Korea
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15
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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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16
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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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17
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Fang D, Chen S, Li Y, Monserrat B. Direct band gap and strong Rashba effect in van der Waals heterostructures of InSe and Sb single layers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:155001. [PMID: 33418556 DOI: 10.1088/1361-648x/abd9ee] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
Van der Waals heterostructures formed by stacking different types of 2D materials are attracting increasing attention due to new emergent physical properties such as interlayer excitons. Recently synthesized atomically thin indium selenide (InSe) and antimony (Sb) individually exhibit interesting electronic properties such as high electron mobility in the former and high hole mobility in the latter. In this work, we present a first-principles investigation on the stability and electronic properties of ultrathin bilayer heterostructures composed of InSe and Sb single layers. The calculated electronic band structures reveal a direct band gap semiconducting nature of the InSe/Sb heterostructures independent of stacking pattern. Taking spin-orbit coupling (SOC) into account, we find a large Rashba spin splitting at the bottom of conduction band, which originates from the atomic SOC with the symmetry breaking in the heterostructure. The strength of the Rashba spin splitting can be tuned by applying in-plane biaxial strain or an out-of-plane external electric field. The presence of large Rashba spin splitting together with a suitable band gap in InSe/Sb bilayer heterostructures make them promising candidates for spin field-effect transistor and optoelectronic device applications.
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Affiliation(s)
- Dangqi Fang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Siyu Chen
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Yaqi Li
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Bartomeu Monserrat
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
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18
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Resonance and antiresonance in Raman scattering in GaSe and InSe crystals. Sci Rep 2021; 11:924. [PMID: 33441595 PMCID: PMC7806833 DOI: 10.1038/s41598-020-79411-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/02/2020] [Indexed: 11/08/2022] Open
Abstract
The temperature effect on the Raman scattering efficiency is investigated in [Formula: see text]-GaSe and [Formula: see text]-InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.
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19
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Molas MR, Tyurnina AV, Zólyomi V, Ott AK, Terry DJ, Hamer MJ, Yelgel C, Babiński A, Nasibulin AG, Ferrari AC, Fal'ko VI, Gorbachev R. Raman spectroscopy of GaSe and InSe post-transition metal chalcogenides layers. Faraday Discuss 2020; 227:163-170. [PMID: 33325929 DOI: 10.1039/d0fd00007h] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
III-VI post-transition metal chalcogenides (InSe and GaSe) are a new class of layered semiconductors, which feature a strong variation of size and type of their band gaps as a function of number of layers (N). Here, we investigate exfoliated layers of InSe and GaSe ranging from bulk crystals down to monolayer, encapsulated in hexagonal boron nitride, using Raman spectroscopy. We present the N-dependence of both intralayer vibrations within each atomic layer, as well as of the interlayer shear and layer breathing modes. A linear chain model can be used to describe the evolution of the peak positions as a function of N, consistent with first principles calculations.
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Affiliation(s)
- Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warszawa, Poland
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20
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Valley interference and spin exchange at the atomic scale in silicon. Nat Commun 2020; 11:6124. [PMID: 33257680 PMCID: PMC7705737 DOI: 10.1038/s41467-020-19835-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 10/29/2020] [Indexed: 11/23/2022] Open
Abstract
Tunneling is a fundamental quantum process with no classical equivalent, which can compete with Coulomb interactions to give rise to complex phenomena. Phosphorus dopants in silicon can be placed with atomic precision to address the different regimes arising from this competition. However, they exploit wavefunctions relying on crystal band symmetries, which tunneling interactions are inherently sensitive to. Here we directly image lattice-aperiodic valley interference between coupled atoms in silicon using scanning tunneling microscopy. Our atomistic analysis unveils the role of envelope anisotropy, valley interference and dopant placement on the Heisenberg spin exchange interaction. We find that the exchange can become immune to valley interference by engineering in-plane dopant placement along specific crystallographic directions. A vacuum-like behaviour is recovered, where the exchange is maximised to the overlap between the donor orbitals, and pair-to-pair variations limited to a factor of less than 10 considering the accuracy in dopant positioning. This robustness remains over a large range of distances, from the strongly Coulomb interacting regime relevant for high-fidelity quantum computation to strongly coupled donor arrays of interest for quantum simulation in silicon. Coupled donor wavefunctions in silicon are spatially resolved to evidence valley interference processes. An atomic-scale understanding of the interplay between interference, envelope anisotropy and crystal symmetries unveils a placement strategy compatible with existing technology where the exchange is insensitive to interference.
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21
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Molecular Beam Epitaxy of Layered Group III Metal Chalcogenides on GaAs(001) Substrates. MATERIALS 2020; 13:ma13163447. [PMID: 32764315 PMCID: PMC7475857 DOI: 10.3390/ma13163447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 11/17/2022]
Abstract
Development of molecular beam epitaxy (MBE) of two-dimensional (2D) layered materials is an inevitable step in realizing novel devices based on 2D materials and heterostructures. However, due to existence of numerous polytypes and occurrence of additional phases, the synthesis of 2D films remains a difficult task. This paper reports on MBE growth of GaSe, InSe, and GaTe layers and related heterostructures on GaAs(001) substrates by using a Se valve cracking cell and group III metal effusion cells. The sophisticated self-consistent analysis of X-ray diffraction, transmission electron microscopy, and Raman spectroscopy data was used to establish the correlation between growth conditions, formed polytypes and additional phases, surface morphology and crystalline structure of the III–VI 2D layers. The photoluminescence and Raman spectra of the grown films are discussed in detail to confirm or correct the structural findings. The requirement of a high growth temperature for the fabrication of optically active 2D layers was confirmed for all materials. However, this also facilitated the strong diffusion of group III metals in III–VI and III–VI/II–VI heterostructures. In particular, the strong In diffusion into the underlying ZnSe layers was observed in ZnSe/InSe/ZnSe quantum well structures, and the Ga diffusion into the top InSe layer grown at ~450 °C was confirmed by the Raman data in the InSe/GaSe heterostructures. The results on fabrication of the GaSe/GaTe quantum well structures are presented as well, although the choice of optimum growth temperatures to make them optically active is still a challenge.
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22
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Kang W, Liu X, Zeng W, Zhang Y, Qi L, Liu J, Fang L, Zhou M. Tunable electronic structures and half-metallicity in two-dimensional InSe functionalized with magnetic superatom. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:365501. [PMID: 32353836 DOI: 10.1088/1361-648x/ab8eca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Based on first-principles calculations, we investigate the geometric, energetic and electronic properties of two-dimensional (2D) InSe functionalized with magnetic superatoms (MnCl3). As a nonmagnetic semiconductor, 2D InSe exhibits non-covalent interaction with MnCl3and provides an ideal substrate for the assembly of magnetic superatoms. We show that with a low coverage of MnCl3, the functionalized system behaves as a magnetic semiconductor with spin-polarized superatomic states residing inside the energy gap of InSe. When the coverage becomes higher, the system has one spin channel crossing Fermi level while the other remains insulating, thus being half-metallic. We further demonstrate electric field effects on the functionalized system, and reveal that half metal with 100% spin polarization can be achieved at a lower coverage due to the field induced charge transfer, which downshifts the unoccupied bands of one spin component so that they become partially filled. These findings are generally applicable, demonstrating the great promise of combining superatom assembly with electric gating for controllable and versatile 2D spintronics.
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Affiliation(s)
- Wei Kang
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Xiaoqing Liu
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Wen Zeng
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Yixin Zhang
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Lin Qi
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
| | - Jun Liu
- School of Science, Chongqing University of Posts and Telecommunication, Chongqing 400064, People's Republic of China
| | - Liang Fang
- College of Physics, Chongqing University, Chongqing 400044, People's Republic of China
| | - Miao Zhou
- Key Laboratory of Optoelectronic Technology and System of Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, People's Republic of China
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23
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Mannu A, Di Pietro ME, Mele A. Band-Gap Energies of Choline Chloride and Triphenylmethylphosphoniumbromide-Based Systems. Molecules 2020; 25:molecules25071495. [PMID: 32218347 PMCID: PMC7180541 DOI: 10.3390/molecules25071495] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/19/2020] [Accepted: 03/23/2020] [Indexed: 11/16/2022] Open
Abstract
UV-VIS spectroscopy analysis of six mixtures containing choline chloride or triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies were compared to those relative to known choline chloride-containing deep band-gap systems. The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the smallest transition energy ever reported to date for such kind of systems.
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Affiliation(s)
- Alberto Mannu
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy; (M.E.D.P.)
- Correspondence:
| | - Maria Enrica Di Pietro
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy; (M.E.D.P.)
| | - Andrea Mele
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano, Italy; (M.E.D.P.)
- CNR-SCITEC Istituto di Scienze e Tecnologie Chimiche, Via Alfonso Corti 12, 20133 Milano, Italy
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24
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Ubrig N, Ponomarev E, Zultak J, Domaretskiy D, Zólyomi V, Terry D, Howarth J, Gutiérrez-Lezama I, Zhukov A, Kudrynskyi ZR, Kovalyuk ZD, Patané A, Taniguchi T, Watanabe K, Gorbachev RV, Fal'ko VI, Morpurgo AF. Design of van der Waals interfaces for broad-spectrum optoelectronics. NATURE MATERIALS 2020; 19:299-304. [PMID: 32015532 DOI: 10.1038/s41563-019-0601-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 12/20/2019] [Indexed: 05/12/2023]
Abstract
Van der Waals (vdW) interfaces based on 2D materials are promising for optoelectronics, as interlayer transitions between different compounds allow tailoring of the spectral response over a broad range. However, issues such as lattice mismatch or a small misalignment of the constituent layers can drastically suppress electron-photon coupling for these interlayer transitions. Here, we engineered type-II interfaces by assembling atomically thin crystals that have the bottom of the conduction band and the top of the valence band at the Γ point, and thus avoid any momentum mismatch. We found that these van der Waals interfaces exhibit radiative optical transitions irrespective of the lattice constant, the rotational and/or translational alignment of the two layers or whether the constituent materials are direct or indirect gap semiconductors. Being robust and of general validity, our results broaden the scope of future optoelectronics device applications based on two-dimensional materials.
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Affiliation(s)
- Nicolas Ubrig
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland.
- Group of Applied Physics, University of Geneva, Geneva, Switzerland.
| | - Evgeniy Ponomarev
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Group of Applied Physics, University of Geneva, Geneva, Switzerland
| | - Johanna Zultak
- National Graphene Institute, University of Manchester, Manchester, UK
- School of Physics & Astronomy, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, Manchester, UK
| | - Daniil Domaretskiy
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Group of Applied Physics, University of Geneva, Geneva, Switzerland
| | - Viktor Zólyomi
- National Graphene Institute, University of Manchester, Manchester, UK
| | - Daniel Terry
- National Graphene Institute, University of Manchester, Manchester, UK
- School of Physics & Astronomy, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, Manchester, UK
| | - James Howarth
- National Graphene Institute, University of Manchester, Manchester, UK
- School of Physics & Astronomy, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, Manchester, UK
| | - Ignacio Gutiérrez-Lezama
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Group of Applied Physics, University of Geneva, Geneva, Switzerland
| | - Alexander Zhukov
- National Graphene Institute, University of Manchester, Manchester, UK
- School of Physics & Astronomy, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, Manchester, UK
| | | | - Zakhar D Kovalyuk
- Institute for Problems of Materials Science, NAS of Ukraine, Chernivtsi Branch, Chernivtsi, Ukraine
| | - Amalia Patané
- School of Physics & Astronomy, The University of Nottingham, Nottingham, UK
| | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | - Roman V Gorbachev
- National Graphene Institute, University of Manchester, Manchester, UK
- School of Physics & Astronomy, University of Manchester, Manchester, UK
- Henry Royce Institute for Advanced Materials, Manchester, UK
| | - Vladimir I Fal'ko
- National Graphene Institute, University of Manchester, Manchester, UK.
- School of Physics & Astronomy, University of Manchester, Manchester, UK.
- Henry Royce Institute for Advanced Materials, Manchester, UK.
| | - Alberto F Morpurgo
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland.
- Group of Applied Physics, University of Geneva, Geneva, Switzerland.
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25
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Hu S, Zhang Q, Luo X, Zhang X, Wang T, Cheng Y, Jie W, Zhao J, Mei T, Gan X. Au-InSe van der Waals Schottky junctions with ultralow reverse current and high photosensitivity. NANOSCALE 2020; 12:4094-4100. [PMID: 32022065 DOI: 10.1039/c9nr08791e] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The Schottky junction, composed of a rectifying metal-semiconductor interface, is an essential component for microelectronic and optoelectronic devices. However, due to the considerable reverse tunneling current, typical Schottky junctions cannot be widely applied in devices requiring high signal-to-noise ratios, such as photodetectors with high detectivity. Here, a van der Waals (vdW) Schottky junction is constructed by mechanically stacking a gold (Au) electrode onto a multilayer indium selenide (InSe) nanosheet, which shows an ultralow reverse current in sub-picoamperes and an excellent rectification ratio exceeding 106 at room temperature. The reverse current, which corresponds to the thermionic emission transport model, is independent of the applied reverse bias. As a result, the Au-InSe vdW Schottky junction device can function as an ultrasensitive photodetector with a photodetectivity over 2.4 × 1015 Jones, corresponding to a photoresponsivity of 853 A W-1 and a light on/off ratio exceeding 1 × 107. The work offers an idea for investigating electronic and optoelectronic devices with high signal-to-noise ratios based on vdW Schottky junctions.
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Affiliation(s)
- Siqi Hu
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
| | - Qiao Zhang
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
| | - Xiaoguang Luo
- Shannxi Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710129, China
| | - Xutao Zhang
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
| | - Tao Wang
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yingchun Cheng
- Shannxi Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710129, China
| | - Wanqi Jie
- State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jianlin Zhao
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
| | - Ting Mei
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
| | - Xuetao Gan
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
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26
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Shi LB, Cao S, Yang M, You Q, Zhang KC, Bao Y, Zhang YJ, Niu YY, Qian P. Theoretical prediction of intrinsic electron mobility of monolayer InSe: first-principles calculation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:065306. [PMID: 31671411 DOI: 10.1088/1361-648x/ab534f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Recently, a novel two-dimensional (2D) semiconductor, InSe, has attracted great attention due to its potential applications in optoelectronic devices and field effect transistors. In this study, phonon-limited mobility is investigated by the first-principles calculation. At 300 K, the intrinsic electron mobilities calculated from the electron-phonon coupling (EPC) matrix element are as high as [Formula: see text] (zigzag direction) and [Formula: see text] [Formula: see text] (Armchair direction), respectively. The deformation potential theory (DPT) based on longitudinal acoustic and optical phonon scattering is also employed to investigate electron mobility. The mobility from optical phonon scattering is much higher than that from longitudinal acoustic phonon scattering. If the polarization characteristics of InSe are not considered, the electron mobility calculated from EPC matrix element is closed to that from the longitudinal acoustic phonon DPT. In this study, we have also investigated the effect of polarization properties in 2D InSe on electron mobility. At 300 K, the electron mobility for including Fröhlich interaction is reduced to [Formula: see text] and [Formula: see text] [Formula: see text]. Therefore, the electron mobility for InSe is controlled by the scattering from polar phonons. The mobility can be increased to [Formula: see text] and [Formula: see text] [Formula: see text] under 4% biaxial strain. This result is compared with the experiment, and some disagreements are explained.
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Affiliation(s)
- Li-Bin Shi
- School of Mathematics and Physics, Bohai University, Liaoning Jinzhou 121013, People's Republic of China
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27
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Singh H, Singh P, Singh R, Sharma J, Singh AP, Kumar A, Thakur A. Composition dependent structural phase transition and optical band gap tuning in InSe thin films. Heliyon 2019; 5:e02933. [PMID: 31844773 PMCID: PMC6895580 DOI: 10.1016/j.heliyon.2019.e02933] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/19/2019] [Accepted: 11/25/2019] [Indexed: 11/30/2022] Open
Abstract
Bulk alloys of In x Se100-x (x = 5, 10, 20, 30, 40 and 50) are prepared using melt quenching technique. Thin films having thickness ~750 nm of these prepared bulk alloys are fabricated using thermal evaporation technique on glass substrate. The as-deposited In x Se100-x thin films with x ≤ 40 are amorphous and In50Se50 thin film is crystalline in nature verified from X-ray diffraction (XRD). The change in morphology of deposited thin films with indium content also verifies structural phase transition and found that the phase transition started with x = 40 which is not detected in XRD pattern. The drastic change in transmission is found with 50% indium content. In50Se50 thin film has less than 30% transmission whereas other films are highly transparent. Optical band gap is calculated using Tauc's plot and decrease in optical band gap is observed with indium content. The variation of optical band gap from 1.88 eV to 1.12 eV is achieved with indium content of 5%-50%. The structural transition and change in optical band gap depict that InSe thin films are potential candidates in various technological applications.
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Affiliation(s)
- Harpreet Singh
- Department of Physics, Punjabi University, Patiala, 147 002, Punjab, India.,Advanced Materials Research Lab, Department of Basic and Applied Sciences, Punjabi University, Patiala, 147 002, Punjab, India
| | - Palwinder Singh
- Department of Physics, Punjabi University, Patiala, 147 002, Punjab, India.,Advanced Materials Research Lab, Department of Basic and Applied Sciences, Punjabi University, Patiala, 147 002, Punjab, India
| | - Randhir Singh
- Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, 140 407, India
| | - Jeewan Sharma
- Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, 140 407, India
| | - A P Singh
- Department of Physics, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, Punjab, 144 011, India
| | - Akshay Kumar
- Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, 140 407, India
| | - Anup Thakur
- Advanced Materials Research Lab, Department of Basic and Applied Sciences, Punjabi University, Patiala, 147 002, Punjab, India
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28
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Lugovskoi AV, Katsnelson MI, Rudenko AN. Strong Electron-Phonon Coupling and its Influence on the Transport and Optical Properties of Hole-Doped Single-Layer InSe. PHYSICAL REVIEW LETTERS 2019; 123:176401. [PMID: 31702262 DOI: 10.1103/physrevlett.123.176401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Indexed: 06/10/2023]
Abstract
We show that hole states in recently discovered single-layer InSe are strongly renormalized by the coupling with acoustic phonons. The coupling is enhanced significantly at moderate hole doping (∼10^{13} cm^{-2}) due to hexagonal warping of the Fermi surface. While the system remains dynamically stable, its electron-phonon spectral function exhibits sharp low-energy resonances, leading to the formation of satellite quasiparticle states near the Fermi energy. Such many-body renormalization is predicted to have two important consequences. First, it significantly suppresses charge carrier mobility reaching ∼1 cm^{2} V^{-1} s^{-1} at 100 K in a freestanding sample. Second, it gives rise to unusual temperature-dependent optical excitations in the midinfrared region. Relatively small charge carrier concentrations and realistic temperatures suggest that these excitations may be observed experimentally.
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Affiliation(s)
- A V Lugovskoi
- Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands
| | - M I Katsnelson
- Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, 620002 Ekaterinburg, Russia
| | - A N Rudenko
- Institute for Molecules and Materials, Radboud University, Heijendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands
- Theoretical Physics and Applied Mathematics Department, Ural Federal University, 620002 Ekaterinburg, Russia
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
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29
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Pham KD, Nguyen TD, Phuc HV, Hieu NN, Bui H, Amin B, Nguyen CV. Strain and electric field engineering of band alignment in InSe/Ca(OH)2 heterostructure. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.136649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Brotons-Gisbert M, Proux R, Picard R, Andres-Penares D, Branny A, Molina-Sánchez A, Sánchez-Royo JF, Gerardot BD. Out-of-plane orientation of luminescent excitons in two-dimensional indium selenide. Nat Commun 2019; 10:3913. [PMID: 31477714 PMCID: PMC6718420 DOI: 10.1038/s41467-019-11920-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 07/30/2019] [Indexed: 11/08/2022] Open
Abstract
Van der Waals materials offer a wide range of atomic layers with unique properties that can be easily combined to engineer novel electronic and photonic devices. A missing ingredient of the van der Waals platform is a two-dimensional crystal with naturally occurring out-of-plane luminescent dipole orientation. Here we measure the far-field photoluminescence intensity distribution of bulk InSe and two-dimensional InSe, WSe2 and MoSe2. We demonstrate, with the support of ab-initio calculations, that layered InSe flakes sustain luminescent excitons with an intrinsic out-of-plane orientation, in contrast with the in-plane orientation of dipoles we find in two-dimensional WSe2 and MoSe2 at room-temperature. These results, combined with the high tunability of the optical response and outstanding transport properties, position layered InSe as a promising semiconductor for novel optoelectronic devices, in particular for hybrid integrated photonic chips which exploit the out-of-plane dipole orientation.
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Affiliation(s)
- Mauro Brotons-Gisbert
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Raphaël Proux
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Raphaël Picard
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Daniel Andres-Penares
- ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071, Valencia, Spain
| | - Artur Branny
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, UK
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 106 91, Sweden
| | - Alejandro Molina-Sánchez
- ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071, Valencia, Spain
- International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga, 4715-330, Braga, Portugal
| | - Juan F Sánchez-Royo
- ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071, Valencia, Spain.
| | - Brian D Gerardot
- Institute of Photonics and Quantum Sciences, SUPA, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
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31
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Shubina TV, Desrat W, Moret M, Tiberj A, Briot O, Davydov VY, Platonov AV, Semina MA, Gil B. InSe as a case between 3D and 2D layered crystals for excitons. Nat Commun 2019; 10:3479. [PMID: 31375686 PMCID: PMC6677765 DOI: 10.1038/s41467-019-11487-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/17/2019] [Indexed: 11/09/2022] Open
Abstract
InSe is a promising material in many aspects where the role of excitons is decisive. Here we report the sequential appearance in its luminescence of the exciton, the biexciton, and the P-band of the exciton-exciton scattering while the excitation power increases. The strict energy and momentum conservation rules of the P-band are used to reexamine the exciton binding energy. The new value ≥20 meV is markedly higher than the currently accepted one (14 meV), being however well consistent with the robustness of the excitons up to room temperature. A peak controlled by the Sommerfeld factor is found near the bandgap (~1.36 eV). Our findings supported by theoretical calculations taking into account the anisotropic material parameters question the pure three-dimensional character of the exciton in InSe, assumed up to now. The refined character and parameters of the exciton are of paramount importance for the successful application of InSe in nanophotonics.
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Affiliation(s)
- T V Shubina
- Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia.
| | - W Desrat
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France.
| | - M Moret
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France
| | - A Tiberj
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France
| | - O Briot
- Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France
| | - V Yu Davydov
- Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia
| | - A V Platonov
- Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia
| | - M A Semina
- Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia
| | - B Gil
- Ioffe Institute, 26 Politekhnicheskaya, St Petersburg, 194021, Russia.,Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, Montpellier, FR-34095, France
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32
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Sang DK, Wen B, Gao S, Zeng Y, Meng F, Guo Z, Zhang H. Electronic and Optical Properties of Two-Dimensional Tellurene: From First-Principles Calculations. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1075. [PMID: 31357462 PMCID: PMC6722590 DOI: 10.3390/nano9081075] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 02/04/2023]
Abstract
Tellurene is a new-emerging two-dimensional anisotropic semiconductor, with fascinating electric and optical properties that differ dramatically from the bulk counterpart. In this work, the layer dependent electronic and optical properties of few-layer Tellurene has been calculated with the density functional theory (DFT). It shows that the band gap of the Tellurene changes from direct to indirect when layer number changes from monolayer (1 L) to few-layers (2 L-6 L) due to structural reconstruction. Tellurene also has an energy gap that can be tuned from 1.0 eV (1 L) to 0.3 eV (6 L). Furthermore, due to the interplay of spin-orbit coupling (SOC) and disappearance of inversion symmetry in odd-numbered layer structures resulting in the anisotropic SOC splitting, the decrease of the band gap with an increasing layer number is not monotonic but rather shows an odd-even quantum confinement effect. The optical results in Tellurene are layer dependent and different in E ⊥ C and E || C directions. The correlations between the structure, the electronic and optical properties of the Tellurene have been identified. Despite the weak nature of interlayer forces in their structure, their electronic and optical properties are highly dependent on the number of layers and highly anisotropic. These results are essential in the realization of its full potential and recommended for experimental exploration.
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Affiliation(s)
- David K Sang
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
| | - Bo Wen
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
| | - Shan Gao
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
| | - Yonghong Zeng
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
| | - Fanxu Meng
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
| | - Zhinan Guo
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China.
| | - Han Zhang
- Shenzhen Engineering Laboratory of Phosphorene and Optoelectronics, Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China.
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33
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Hamer MJ, Zultak J, Tyurnina AV, Zólyomi V, Terry D, Barinov A, Garner A, Donoghue J, Rooney AP, Kandyba V, Giampietri A, Graham A, Teutsch N, Xia X, Koperski M, Haigh SJ, Fal'ko VI, Gorbachev RV, Wilson NR. Indirect to Direct Gap Crossover in Two-Dimensional InSe Revealed by Angle-Resolved Photoemission Spectroscopy. ACS NANO 2019; 13:2136-2142. [PMID: 30676744 DOI: 10.1021/acsnano.8b08726] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Atomically thin films of III-VI post-transition metal chalcogenides (InSe and GaSe) form an interesting class of two-dimensional semiconductors that feature a strong variation of their band gap as a function of the number of layers in the crystal and, specifically for InSe, an expected crossover from a direct gap in the bulk to a weakly indirect band gap in monolayers and bilayers. Here, we apply angle-resolved photoemission spectroscopy with submicrometer spatial resolution (μARPES) to visualize the layer-dependent valence band structure of mechanically exfoliated crystals of InSe. We show that for one-layer and two-layer InSe the valence band maxima are away from the Γ-point, forming an indirect gap, with the conduction band edge known to be at the Γ-point. In contrast, for six or more layers the band gap becomes direct, in good agreement with theoretical predictions. The high-quality monolayer and bilayer samples enable us to resolve, in the photoluminescence spectra, the band-edge exciton (A) from the exciton (B) involving holes in a pair of deeper valence bands, degenerate at Γ, with a splitting that agrees with both μARPES data and the results of DFT modeling. Due to the difference in symmetry between these two valence bands, light emitted by the A-exciton should be predominantly polarized perpendicular to the plane of the two-dimensional crystal, which we have verified for few-layer InSe crystals.
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Affiliation(s)
- Matthew J Hamer
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Johanna Zultak
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Anastasia V Tyurnina
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Viktor Zólyomi
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Daniel Terry
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Alexei Barinov
- Elettra - Sincrotrone Trieste , S.C.p.A., Basovizza ( TS ), 34149 , Italy
| | - Alistair Garner
- School of Materials , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Jack Donoghue
- School of Materials , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Aidan P Rooney
- School of Materials , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Viktor Kandyba
- Elettra - Sincrotrone Trieste , S.C.p.A., Basovizza ( TS ), 34149 , Italy
| | - Alessio Giampietri
- Elettra - Sincrotrone Trieste , S.C.p.A., Basovizza ( TS ), 34149 , Italy
| | - Abigail Graham
- Department of Physics , University of Warwick , Coventry , CV4 7AL , U.K
| | - Natalie Teutsch
- Department of Physics , University of Warwick , Coventry , CV4 7AL , U.K
| | - Xue Xia
- Department of Physics , University of Warwick , Coventry , CV4 7AL , U.K
| | - Maciej Koperski
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Sarah J Haigh
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- School of Materials , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Vladimir I Fal'ko
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- Henry Royce Institute , Oxford Road , Manchester , M13 9PL , U.K
| | - Roman V Gorbachev
- School of Physics and Astronomy , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- Henry Royce Institute , Oxford Road , Manchester , M13 9PL , U.K
| | - Neil R Wilson
- Department of Physics , University of Warwick , Coventry , CV4 7AL , U.K
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34
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Pham KD, Hieu NN, Bui LM, Phuc HV, Hoi BD, Tu LT, Bach LG, Ilyasov VV, Amin B, Idrees M, Nguyen CV. Vertical strain and electric field tunable electronic properties of type-II band alignment C2N/InSe van der Waals heterostructure. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2018.12.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Huang W, Gan L, Li H, Ma Y, Zhai T. Phase‐Engineered Growth of Ultrathin InSe Flakes by Chemical Vapor Deposition for High‐Efficiency Second Harmonic Generation. Chemistry 2018; 24:15678-15684. [DOI: 10.1002/chem.201803634] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 07/16/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Wenjuan Huang
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering Huazhong University of, Science and Technology (HUST) Wuhan 430074 P. R. China
| | - Lin Gan
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering Huazhong University of, Science and Technology (HUST) Wuhan 430074 P. R. China
| | - Huiqiao Li
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering Huazhong University of, Science and Technology (HUST) Wuhan 430074 P. R. China
| | - Ying Ma
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering Huazhong University of, Science and Technology (HUST) Wuhan 430074 P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering Huazhong University of, Science and Technology (HUST) Wuhan 430074 P. R. China
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36
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Li Y, Wang T, Wang H, Li Z, Chen Y, West D, Sankar R, Ulaganathan RK, Chou F, Wetzel C, Xu CY, Zhang S, Shi SF. Enhanced Light Emission from the Ridge of Two-Dimensional InSe Flakes. NANO LETTERS 2018; 18:5078-5084. [PMID: 30021441 DOI: 10.1021/acs.nanolett.8b01940] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
InSe, a newly rediscovered two-dimensional (2D) semiconductor, possesses superior electrical and optical properties as a direct-band-gap semiconductor with high mobility from bulk to atomically thin layers and is drastically different from transition-metal dichalcogenides, in which the direct band gap only exists at the single-layer limit. However, absorption in InSe is mostly dominated by an out-of-plane dipole contribution, which results in the limited absorption of normally incident light that can only excite the in-plane dipole at resonance. To address this challenge, we have explored a unique geometric ridge state of the 2D flake without compromising the sample quality. We observed the enhanced absorption at the ridge over a broad range of excitation frequencies from photocurrent and photoluminescence (PL) measurements. In addition, we have discovered new PL peaks at low temperatures due to defect states on the ridge, which can be as much as ∼60 times stronger than the intrinsic PL peak of InSe. Interestingly, the PL of the defects is highly tunable through an external electrical field, which can be attributed to the Stark effect of the localized defects. InSe ridges thus provide new avenues for manipulating light-matter interactions and defect engineering that are vitally crucial for novel optoelectronic devices based on 2D semiconductors.
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Affiliation(s)
- Yang Li
- School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China
| | | | | | - Zhipeng Li
- School of Chemistry and Chemical Engineering , Shanghai Jiao Tong University , Shanghai 200240 , China
| | | | | | - Raman Sankar
- Institute of Physics , Academia Sinica , Nangang, Taipei , Taiwan 11529 , Taiwan
- Center for Condensed Matter Science , National Taiwan University , Taipei , Taiwan 10617 , Taiwan
| | - Rajesh K Ulaganathan
- Institute of Physics , Academia Sinica , Nangang, Taipei , Taiwan 11529 , Taiwan
- Center for Condensed Matter Science , National Taiwan University , Taipei , Taiwan 10617 , Taiwan
| | - Fangcheng Chou
- Institute of Physics , Academia Sinica , Nangang, Taipei , Taiwan 11529 , Taiwan
- Center for Condensed Matter Science , National Taiwan University , Taipei , Taiwan 10617 , Taiwan
| | | | - Cheng-Yan Xu
- School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China
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37
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Moro F, Bhuiyan MA, Kudrynskyi ZR, Puttock R, Kazakova O, Makarovsky O, Fay MW, Parmenter C, Kovalyuk ZD, Fielding AJ, Kern M, van Slageren J, Patanè A. Room Temperature Uniaxial Magnetic Anisotropy Induced By Fe-Islands in the InSe Semiconductor Van Der Waals Crystal. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1800257. [PMID: 30027057 PMCID: PMC6051381 DOI: 10.1002/advs.201800257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/08/2018] [Indexed: 05/28/2023]
Abstract
The controlled manipulation of the spin and charge of electrons in a semiconductor has the potential to create new routes to digital electronics beyond Moore's law, spintronics, and quantum detection and imaging for sensing applications. These technologies require a shift from traditional semiconducting and magnetic nanostructured materials. Here, a new material system is reported, which comprises the InSe semiconductor van der Waals crystal that embeds ferromagnetic Fe-islands. In contrast to many traditional semiconductors, the electronic properties of InSe are largely preserved after the incorporation of Fe. Also, this system exhibits ferromagnetic resonances and a large uniaxial magnetic anisotropy at room temperature, offering opportunities for the development of functional devices that integrate magnetic and semiconducting properties within the same material system.
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Affiliation(s)
- Fabrizio Moro
- School of Physics and AstronomyThe University of NottinghamNG7 2RDNottinghamUK
- Department of PhysicsChemistry and BiologyLinköping University581 83LinköpingSweden
| | - Mahabub A. Bhuiyan
- School of Physics and AstronomyThe University of NottinghamNG7 2RDNottinghamUK
| | | | - Robert Puttock
- National Physical LaboratoryHampton RoadTW11 0LWTeddingtonUK
| | - Olga Kazakova
- National Physical LaboratoryHampton RoadTW11 0LWTeddingtonUK
| | - Oleg Makarovsky
- School of Physics and AstronomyThe University of NottinghamNG7 2RDNottinghamUK
| | - Michael W. Fay
- Nanoscale and Microscale Research CentreThe University of NottinghamNG7 2RDNottinghamUK
| | - Christopher Parmenter
- Nanoscale and Microscale Research CentreThe University of NottinghamNG7 2RDNottinghamUK
| | - Zakhar D. Kovalyuk
- Institute for Problems of Materials ScienceThe National Academy of Sciences of Ukraine58001ChernivtsiUkraine
| | | | - Michal Kern
- Institut für Physikalische Chemie and the Center for Integrated Quantum Science and TechnologyUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Joris van Slageren
- Institut für Physikalische Chemie and the Center for Integrated Quantum Science and TechnologyUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Amalia Patanè
- School of Physics and AstronomyThe University of NottinghamNG7 2RDNottinghamUK
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38
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Hamer M, Tóvári E, Zhu M, Thompson MD, Mayorov A, Prance J, Lee Y, Haley RP, Kudrynskyi ZR, Patanè A, Terry D, Kovalyuk ZD, Ensslin K, Kretinin AV, Geim A, Gorbachev R. Gate-Defined Quantum Confinement in InSe-Based van der Waals Heterostructures. NANO LETTERS 2018; 18:3950-3955. [PMID: 29763556 DOI: 10.1021/acs.nanolett.8b01376] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Indium selenide, a post-transition metal chalcogenide, is a novel two-dimensional (2D) semiconductor with interesting electronic properties. Its tunable band gap and high electron mobility have already attracted considerable research interest. Here we demonstrate strong quantum confinement and manipulation of single electrons in devices made from few-layer crystals of InSe using electrostatic gating. We report on gate-controlled quantum dots in the Coulomb blockade regime as well as one-dimensional quantization in point contacts, revealing multiple plateaus. The work represents an important milestone in the development of quality devices based on 2D materials and makes InSe a prime candidate for relevant electronic and optoelectronic applications.
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Affiliation(s)
- Matthew Hamer
- School of Physics , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Endre Tóvári
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Mengjian Zhu
- School of Physics , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Michael D Thompson
- Department of Physics , University of Lancaster , Bailrigg , Lancaster , LA1 4YW , U.K
| | - Alexander Mayorov
- Centre for Advanced 2D Materials , National University of Singapore , 6 Science Drive 2 , Singapore 117546 , Singapore
| | - Jonathon Prance
- Department of Physics , University of Lancaster , Bailrigg , Lancaster , LA1 4YW , U.K
| | - Yongjin Lee
- Solid State Physics Laboratory , ETH Zurich , Otto-Stern-Weg 1 , 8093 Zürich , Switzerland
| | - Richard P Haley
- Department of Physics , University of Lancaster , Bailrigg , Lancaster , LA1 4YW , U.K
| | - Zakhar R Kudrynskyi
- School of Physics and Astronomy , University of Nottingham , Nottingham NG7 2RD , U.K
| | - Amalia Patanè
- School of Physics and Astronomy , University of Nottingham , Nottingham NG7 2RD , U.K
| | - Daniel Terry
- School of Physics , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Zakhar D Kovalyuk
- National Academy of Sciences of Ukraine , Institute for Problems of Materials Science , UA-58001 , Chernovtsy , Ukraine
| | - Klaus Ensslin
- Solid State Physics Laboratory , ETH Zurich , Otto-Stern-Weg 1 , 8093 Zürich , Switzerland
| | - Andrey V Kretinin
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- School of Materials , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Andre Geim
- School of Physics , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
| | - Roman Gorbachev
- School of Physics , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
- National Graphene Institute , University of Manchester , Oxford Road , Manchester , M13 9PL , U.K
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39
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Hu T, Zhou J, Dong J. Strain induced new phase and indirect-direct band gap transition of monolayer InSe. Phys Chem Chem Phys 2018; 19:21722-21728. [PMID: 28776623 DOI: 10.1039/c7cp03558f] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The effect of in-plane strain on monolayer InSe has been systematically investigated by using first-principles calculations. It is found that monolayer InSe exhibits superior mechanical flexibility, which can sustain a tensile strain up to 27% in the armchair direction. More importantly, a new phase with inversion symmetry denoted as phase-II is obtained when the tensile strain increases over 25% along the zigzag direction, which is predicted to be metallic and thermodynamically stable at room temperature. And the phase-II InSe could show an out-of-plane negative Poisson's ratio after the uniaxial tensile strain is larger than 5%. Moreover, both uniaxial and biaxial compressive strains can trigger the indirect-to-direct band gap transition in the pristine monolayer InSe and its band gap decreases monotonously with the applied tensile strain, which offers an effective method to tune the electronic properties of monolayer InSe for its promising application in electronics and optoelectronics.
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Affiliation(s)
- Ting Hu
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, 210094, China
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40
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Song C, Fan F, Xuan N, Huang S, Zhang G, Wang C, Sun Z, Wu H, Yan H. Largely Tunable Band Structures of Few-Layer InSe by Uniaxial Strain. ACS APPLIED MATERIALS & INTERFACES 2018; 10:3994-4000. [PMID: 29322766 DOI: 10.1021/acsami.7b17247] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Because of the strong quantum confinement effect, few-layer γ-InSe exhibits a layer-dependent band gap, spanning the visible and near infrared regions, and thus recently has been drawing tremendous attention. As a two-dimensional material, the mechanical flexibility provides an additional tuning knob for the electronic structures. Here, for the first time, we engineer the band structures of few-layer and bulk-like InSe by uniaxial tensile strain and observe a salient shift of photoluminescence peaks. The shift rate of the optical gap is approximately 90-100 meV per 1% strain for four- to eight-layer samples, which is much larger than that for the widely studied MoS2 monolayer. Density functional theory calculations well reproduce the observed layer-dependent band gaps and the strain effect and reveal that the shift rate decreases with the increasing layer number for few-layer InSe. Our study demonstrates that InSe is a very versatile two-dimensional electronic and optoelectronic material, which is suitable for tunable light emitters, photodetectors, and other optoelectronic devices.
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Affiliation(s)
- Chaoyu Song
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | - Fengren Fan
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | | | - Shenyang Huang
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | - Guowei Zhang
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | - Chong Wang
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | | | - Hua Wu
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
| | - Hugen Yan
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China
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41
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Fan Y, Liu X, Wang J, Ai H, Zhao M. Silicene and germanene on InSe substrates: structures and tunable electronic properties. Phys Chem Chem Phys 2018; 20:11369-11377. [DOI: 10.1039/c8cp00610e] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The tunable electronic properties of Si/InSe and Ge/InSe HLs by applying an external electric field or strain.
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Affiliation(s)
- Yingcai Fan
- Department of Assets Management
- School of Information and Electronic Engineering
- Shandong Technology and Business University
- Yantai 264005
- China
| | - Xiaobiao Liu
- School of Physics and State Key Laboratory of Crystal Materials
- Shandong University
- Jinan 250100
- China
| | - Junru Wang
- School of Physics and State Key Laboratory of Crystal Materials
- Shandong University
- Jinan 250100
- China
| | - Haoqiang Ai
- School of Physics and State Key Laboratory of Crystal Materials
- Shandong University
- Jinan 250100
- China
| | - Mingwen Zhao
- School of Physics and State Key Laboratory of Crystal Materials
- Shandong University
- Jinan 250100
- China
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42
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Wang XP, Li XB, Chen NK, Zhao JH, Chen QD, Sun HB. Electric field analyses on monolayer semiconductors: the example of InSe. Phys Chem Chem Phys 2018; 20:6945-6950. [DOI: 10.1039/c7cp07270h] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Properties of an InSe monolayer under external vertical electric fields.
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Affiliation(s)
- Xue-Peng Wang
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
| | - Xian-Bin Li
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
| | - Nian-Ke Chen
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
| | - Ji-Hong Zhao
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
| | - Qi-Dai Chen
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
| | - Hong-Bo Sun
- State Key Laboratory of Integrated Optoelectronics
- College of Electronic Science and Engineering
- Jilin University
- Changchun
- China
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43
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Kistanov AA, Cai Y, Zhou K, Dmitriev SV, Zhang YW. Effects of graphene/BN encapsulation, surface functionalization and molecular adsorption on the electronic properties of layered InSe: a first-principles study. Phys Chem Chem Phys 2018; 20:12939-12947. [DOI: 10.1039/c8cp01146j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A proper adoption of the n- or p-type dopants allows for the modulation of the work function, the Fermi level pinning, the band bending, and the photo-adsorbing efficiency near the InSe surface/interface.
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Affiliation(s)
- Andrey A. Kistanov
- School of Mechanical and Aerospace Engineering
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Yongqing Cai
- Institute of High Performance Computing
- Agency for Science, Technology and Research
- Singapore 138632
- Singapore
| | - Kun Zhou
- School of Mechanical and Aerospace Engineering
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Sergey V. Dmitriev
- Institute for Metals Superplasticity Problems
- Russian Academy of Sciences
- Ufa 450001
- Russia
- National Research Tomsk State University
| | - Yong-Wei Zhang
- Institute of High Performance Computing
- Agency for Science, Technology and Research
- Singapore 138632
- Singapore
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44
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Amara IB, Hichri A, Jaziri S. Indium selenide monolayer: strain-enhanced optoelectronic response and dielectric environment-tunable 2D exciton features. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:505302. [PMID: 29171963 DOI: 10.1088/1361-648x/aa98f0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electronic and optical performances of the β-InSe monolayer (ML) are considerably boosted by tuning the corresponding band energies through lattice in-plane compressive strain engineering. First principles calculations show an indirect-direct gap transition with a large bandgap size. The crossover is due to different responses of the near-gap state energies with respect to strain. This is explained by the variation of In-Se bond length, the bond nature of near-band-edge electronic orbital and of the momentum angular contribution versus in-plane compressive strain. The effective masses of charge carriers are also found to be highly modulated and significantly light at the indirect-direct-gap transition. The tuned optical response of the resulting direct-gap ML β-InSe is evaluated versus applied energy to infer the allowed optical transitions, dielectric constants, semiconductor-metal behavior and refractive index. The environmental dielectric engineering of exciton behavior of the resulting direct-gap ML β-InSe is handled within the effective mass Wannier-Mott model and is expected to be important. Our results highlight the increase of binding energy and red-shifted exciton energy with decreasing screening substrates, resulting in a stable exciton at room temperature. The intensity and energy of the ground-state exciton emission are expected to be strongly influenced under substrate screening effect. According to our findings, the direct-gap ML β-InSe assures tremendous 2D optoelectronic and nanoelectronic merits that could overcome several limitations of unstrained ML β-InSe.
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Affiliation(s)
- Imen Ben Amara
- Faculté des Sciences de Tunis, Laboratoire de Physique de la Matière Condensée, Université Tunis El Manar Campus Universitaire, 2092, Tunisia
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45
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Photoacoustic and modulated reflectance studies of indirect and direct band gap in van der Waals crystals. Sci Rep 2017; 7:15365. [PMID: 29133933 PMCID: PMC5684221 DOI: 10.1038/s41598-017-15763-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/01/2017] [Indexed: 11/09/2022] Open
Abstract
Photoacoustic (PA) and modulated reflectance (MR) spectroscopy have been applied to study the indirect and direct band gap for van der Waals (vdW) crystals: dichalcogenides (MoS2, MoSe2, MoTe2, HfS2, HfSe2, WS2, WSe2, ReS2, ReSe2, SnS2 and SnSe2) and monochalcogenides (GaS, GaSe, InSe, GeS, and GeSe). It is shown that the indirect band gap can be determined by PA technique while the direct band gap can be probed by MR spectroscopy which is not sensitive to indirect optical transitions. By measuring PA and MR spectra for a given compound and comparing them with each other it is easy to conclude about the band gap character in the investigated compound and the energy difference between indirect and direct band gap. In this work such measurements, comparisons, and analyses have been performed and chemical trends in variation of indirect and direct band gap with the change in atom sizes have been discussed for proper sets of vdW crystals. It is shown that both indirect and direct band gap in vdW crystals follow the well-known chemical trends in semiconductor compounds.
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46
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The Advent of Indium Selenide: Synthesis, Electronic Properties, Ambient Stability and Applications. NANOMATERIALS 2017; 7:nano7110372. [PMID: 29113090 PMCID: PMC5707589 DOI: 10.3390/nano7110372] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 10/28/2017] [Indexed: 12/19/2022]
Abstract
Among the various two-dimensional semiconductors, indium selenide has recently triggered the interest of scientific community, due to its band gap matching the visible region of the electromagnetic spectrum, with subsequent potential applications in optoelectronics and especially in photodetection. In this feature article, we discuss the main issues in the synthesis, the ambient stability and the application capabilities of this novel class of two-dimensional semiconductors, by evidencing open challenges and pitfalls. In particular, we evidence how the growth of single crystals with reduced amount of Se vacancies is crucial in the road map for the exploitation of indium selenide in technology through ambient-stable nanodevices with outstanding values of both mobility of charge carriers and ON/OFF ratio. The surface chemical reactivity of the InSe surface, as well as applications in the fields of broadband photodetection, flexible electronics and solar energy conversion are also discussed.
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47
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Kudrynskyi ZR, Bhuiyan MA, Makarovsky O, Greener JDG, Vdovin EE, Kovalyuk ZD, Cao Y, Mishchenko A, Novoselov KS, Beton PH, Eaves L, Patanè A. Giant Quantum Hall Plateau in Graphene Coupled to an InSe van der Waals Crystal. PHYSICAL REVIEW LETTERS 2017; 119:157701. [PMID: 29077458 DOI: 10.1103/physrevlett.119.157701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 05/07/2023]
Abstract
We report on a "giant" quantum Hall effect plateau in a graphene-based field-effect transistor where graphene is capped by a layer of the van der Waals crystal InSe. The giant quantum Hall effect plateau arises from the close alignment of the conduction band edge of InSe with the Dirac point of graphene. This feature enables the magnetic-field- and electric-field-effect-induced transfer of charge carriers between InSe and the degenerate Landau level states of the adjacent graphene layer, which is coupled by a van der Waals heterointerface to the InSe.
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Affiliation(s)
- Z R Kudrynskyi
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - M A Bhuiyan
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - O Makarovsky
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - J D G Greener
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - E E Vdovin
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Institute of Microelectronics Technology and High Purity Materials, RAS, Chernogolovka 142432, Russia
| | - Z D Kovalyuk
- Institute for Problems of Materials Science, The National Academy of Sciences of Ukraine, Chernivtsi Branch, Chernivtsi 58001, Ukraine
| | - Y Cao
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
- National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
| | - A Mishchenko
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - K S Novoselov
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - P H Beton
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - L Eaves
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - A Patanè
- School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
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48
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Wang D, Li XB, Sun HB. Native defects and substitutional impurities in two-dimensional monolayer InSe. NANOSCALE 2017; 9:11619-11624. [PMID: 28770912 DOI: 10.1039/c7nr03389c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
As a burgeoning two-dimensional (2D) semiconductor, InSe holds unique electronic properties and great promise for novel 2D electronic devices. To advance the development of 2D InSe devices, the exploration of n-type and p-type conductivities of InSe is indispensable. With first-principles calculations, we investigate the properties of native defects and substitutional impurities in monolayer InSe, including formation energies and ionization energies. As the traditional jellium scheme encounters an energy divergence for charged defects in 2D materials, an extrapolation approach is adopted here to obtain convergent energies. We find that In vacancy is a deep acceptor and Se vacancy is an electrically neutral defect. All the studied substitutional dopants at In or Se sites have high ionization energies in the range of 0.41-0.84 eV. However, electrons may transport through the defect-bound band edge states in XSe (X = Cl, Br, and I) as a potential source of n-type conductivity.
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Affiliation(s)
- Dan Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
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49
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Ho PH, Chang YR, Chu YC, Li MK, Tsai CA, Wang WH, Ho CH, Chen CW, Chiu PW. High-Mobility InSe Transistors: The Role of Surface Oxides. ACS NANO 2017; 11:7362-7370. [PMID: 28661128 DOI: 10.1021/acsnano.7b03531] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In search of high-performance field-effect transistors (FETs) made of atomic thin semiconductors, indium selenide (InSe) has held great promise because of its high intrinsic mobility and moderate electronic band gap (1.26 eV). Yet the performance of InSe FETs is decisively determined by the surface oxidation of InSe taking place spontaneously in ambient conditions, setting up a mobility ceiling and causing an uncontrollable current hysteresis. Encapsulation by hexagonal boron nitride (h-BN) has been currently used to cope with this deterioration. Here, we provide insights into the role of surface oxides played in device performance and introduce a dry-oxidation process that forms a dense capping layer on top, where InSe FETs exhibit a record-high two-probe mobility of 423 cm2/V·s at room temperature and 1006 cm2/V·s at liquid nitrogen temperature without the use of h-BN encapsulation or high-κ dielectric screening. Ultrahigh on/off current ratio of >108 and current density of 365 μA/μm can be readily achieved without elaborate engineering of drain/source contacts or gating technique. Thickness-dependent device properties are also studied, with optimized performance shown in FETs comprising of 13 nm thick InSe. The high performance of InSe FETs with ultrathin dry oxide is attributed to the effective unpinning of the Fermi level at the metal contacts, resulting in a low Schottky barrier height of 40 meV in an optimized channel thickness.
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Affiliation(s)
- Po-Hsun Ho
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Yih-Ren Chang
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Yu-Cheng Chu
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Min-Ken Li
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Che-An Tsai
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
| | - Wei-Hua Wang
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
| | - Ching-Hwa Ho
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology , Taipei 10617, Taiwan
| | - Chun-Wei Chen
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei 10617, Taiwan
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50
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Kou L, Du A, Ma Y, Liao T, Chen C. Charging assisted structural phase transitions in monolayer InSe. Phys Chem Chem Phys 2017; 19:22502-22508. [DOI: 10.1039/c7cp04469k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two new phases of InSe with novel electronic properties have been identified by first-principles calculations; charge doping and substrates are suggested as feasible methods to stabilize these structures.
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Affiliation(s)
- Liangzhi Kou
- School of Chemistry
- Physics and Mechanical Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Aijun Du
- School of Chemistry
- Physics and Mechanical Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Yandong Ma
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Ting Liao
- School of Chemistry
- Physics and Mechanical Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Changfeng Chen
- Department of Physics and Astronomy and High Pressure Science and Engineering Center
- University of Nevada
- Las Vegas
- USA
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