1
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Ma L, Wang Y, Liu Y. van der Waals Contact for Two-Dimensional Transition Metal Dichalcogenides. Chem Rev 2024; 124:2583-2616. [PMID: 38427801 DOI: 10.1021/acs.chemrev.3c00697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as highly promising candidates for next-generation electronics owing to their atomically thin structures and surfaces devoid of dangling bonds. However, establishing high-quality metal contacts with TMDs presents a critical challenge, primarily attributed to their ultrathin bodies and delicate lattices. These distinctive characteristics render them susceptible to physical damage and chemical reactions when conventional metallization approaches involving "high-energy" processes are implemented. To tackle this challenge, the concept of van der Waals (vdW) contacts has recently been proposed as a "low-energy" alternative. Within the vdW geometry, metal contacts can be physically laminated or gently deposited onto the 2D channel of TMDs, ensuring the formation of atomically clean and electronically sharp contact interfaces while preserving the inherent properties of the 2D TMDs. Consequently, a considerable number of vdW contact devices have been extensively investigated, revealing unprecedented transport physics or exceptional device performance that was previously unachievable. This review presents recent advancements in vdW contacts for TMD transistors, discussing the merits, limitations, and prospects associated with each device geometry. By doing so, our purpose is to offer a comprehensive understanding of the current research landscape and provide insights into future directions within this rapidly evolving field.
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Affiliation(s)
- Likuan Ma
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yiliu Wang
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yuan Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
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2
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Kwon G, Kim HS, Jeong K, Kim M, Nam GH, Park H, Yoo K, Cho MH. Forming Stable van der Waals Contacts between Metals and 2D Semiconductors. SMALL METHODS 2023; 7:e2300376. [PMID: 37291738 DOI: 10.1002/smtd.202300376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/19/2023] [Indexed: 06/10/2023]
Abstract
High-performing 2D electrical and optical devices can be realized by forming an ideal van der Waals (vdW) metal contact with weak interactions and stable interface states. However, the methods for applying metal contacts while avoiding damage from metal deposition present challenges in realizing a uniform, stable vdW interface. To overcome this problem, this study develops a method for forming vdW contacts using a sacrificial Se buffer layer. This study explores this method by investigating the difference in the Schottky barrier height between the vdW metal contact deposited using a buffer layer, a transferred metal contact, and a conventional directly deposited metal contact using rectification and photovoltaic characteristics of a Schottky diode structure with graphite. Evidently, the Se buffer layer method forms the most stable and ideal vdW contact while preventing Fermi-level pinning. A tungsten diselenide Schottky diode fabricated using these vdW contacts with Au and graphite as the top and bottom electrodes, respectively, exhibits excellent operation with an ideality factor of ≈1, an on/off ratio of > 107 , and coherent properties. Additionally, when using only the vdW Au contact, the electrical and optical properties of the device can be minutely modulated by changing the structure of the Schottky diode.
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Affiliation(s)
- Gihyeon Kwon
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hyeon-Sik Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kwangsik Jeong
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Myeongjin Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Gi Hwan Nam
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hyunjun Park
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kyunghwa Yoo
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Mann-Ho Cho
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
- Department of System Semiconductor Engineering, Yonsei University, Seoul, 03722, Republic of Korea
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3
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Joshi J, Zhou T, Krylyuk S, Davydov AV, Zutic I, Vora PM. Localized Excitons in NbSe 2-MoSe 2 Heterostructures. ACS NANO 2020; 14:8528-8538. [PMID: 32639717 PMCID: PMC8171581 DOI: 10.1021/acsnano.0c02803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Neutral and charged excitons (trions) in atomically thin materials offer important capabilities for photonics, from ultrafast photodetectors to highly efficient light-emitting diodes and lasers. Recent studies of van der Waals (vdW) heterostructures comprised of dissimilar monolayer materials have uncovered a wealth of optical phenomena that are predominantly governed by interlayer interactions. Here, we examine the optical properties in NbSe2-MoSe2 vdW heterostructures, which provide an important model system to study metal-semiconductor interfaces, a common element in optoelectronics. Through low-temperature photoluminescence (PL) microscopy, we discover a sharp emission feature, L1, that is localized at the NbSe2-capped regions of MoSe2. L1 is observed at energies below the commonly studied MoSe2 excitons and trions and exhibits temperature- and power-dependent PL consistent with exciton localization in a confining potential. This PL feature is robust, observed in a variety of samples fabricated with different stacking geometries and cleaning procedures. Using first-principles calculations, we reveal that the confinement potential required for exciton localization naturally arises from the in-plane band bending due to the changes in the electron affinity between pristine MoSe2 and NbSe2-MoSe2 heterostructure. We discuss the implications of our studies for atomically thin optoelectronics devices with atomically sharp interfaces and tunable electronic structures.
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Affiliation(s)
- Jaydeep Joshi
- Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, United States
- Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia 22030, United States
| | - Tong Zhou
- Department of Physics, University at Buffalo, Buffalo, New York 14260, United States
| | - Sergiy Krylyuk
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Albert V. Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Igor Zutic
- Department of Physics, University at Buffalo, Buffalo, New York 14260, United States
| | - Patrick M. Vora
- Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030, United States
- Quantum Science and Engineering Center, George Mason University, Fairfax, Virginia 22030, United States
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4
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Song A, Gao L, Zhang J, Liu X, Hu YZ, Ma TB, Zheng Q, Luo J. Achieving a superlubricating ohmic sliding electrical contact via a 2D heterointerface: a computational investigation. NANOSCALE 2020; 12:7857-7863. [PMID: 32227006 DOI: 10.1039/c9nr09662k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Simultaneously achieving low friction and fine electrical conductance of sliding electrical contacts is a crucial factor but a great challenge for designing high-performance microscale and nanoscale functional devices. Through atomistic simulations, we propose an effective design strategy to obtain both low friction and high conductivity in sliding electrical contacts. By constructing graphene(Gr)/MoS2 two-dimensional (2D) heterojunctions between sliding Cu surfaces, superlubricity can be achieved with a remarkably lowered sliding energy barrier as compared to that of the homogeneous MoS2 lubricated Cu contact. Moreover, by introducing vacancy defects into MoS2 and substituting Cu with active metal Ti, the Schottky and tunneling barriers can be substantially suppressed without losing the superlubricious properties of the tribointerface. Consequently, a high conductivity ohmic contact with low sliding friction could be realized in our proposed Ti-MoS1.5-Gr-Ti system, which provides a potential strategy for tackling the well-known dilemma for high performance sliding electrical contacts.
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Affiliation(s)
- Aisheng Song
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
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5
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Rigosi AF, Hill HM, Krylyuk S, Nguyen NV, Hight Walker AR, Davydov AV, Newell DB. Dielectric Properties of Nb xW 1-xSe 2 Alloys. JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 2019; 124:1-10. [PMID: 34877178 PMCID: PMC7343519 DOI: 10.6028/jres.124.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 06/13/2023]
Abstract
The growth of transition metal dichalcogenide (TMDC) alloys provides an opportunity to experimentally access information elucidating how optical properties change with gradual substitutions in the lattice compared with their pure compositions. In this work, we performed growths of alloyed crystals with stoichiometric compositions between pure forms of NbSe2 and WSe2, followed by an optical analysis of those alloys by utilizing Raman spectroscopy and spectroscopic ellipsometry.
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Affiliation(s)
- Albert F Rigosi
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Heather M Hill
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | - Nhan V Nguyen
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | | | - Albert V Davydov
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - David B Newell
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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6
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Jain A, Szabó Á, Parzefall M, Bonvin E, Taniguchi T, Watanabe K, Bharadwaj P, Luisier M, Novotny L. One-Dimensional Edge Contacts to a Monolayer Semiconductor. NANO LETTERS 2019; 19:6914-6923. [PMID: 31513426 DOI: 10.1021/acs.nanolett.9b02166] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Integration of electrical contacts into van der Waals (vdW) heterostructures is critical for realizing electronic and optoelectronic functionalities. However, to date no scalable methodology for gaining electrical access to buried monolayer two-dimensional (2D) semiconductors exists. Here we report viable edge contact formation to hexagonal boron nitride (hBN) encapsulated monolayer MoS2. By combining reactive ion etching, in situ Ar+ sputtering and annealing, we achieve a relatively low edge contact resistance, high mobility (up to ∼30 cm2 V-1 s-1) and high on-current density (>50 μA/μm at VDS = 3V), comparable to top contacts. Furthermore, the atomically smooth hBN environment also preserves the intrinsic MoS2 channel quality during fabrication, leading to a steep subthreshold swing of 116 mV/dec with a negligible hysteresis. Hence, edge contacts are highly promising for large-scale practical implementation of encapsulated heterostructure devices, especially those involving air sensitive materials, and can be arbitrarily narrow, which opens the door to further shrinkage of 2D device footprint.
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Affiliation(s)
- Achint Jain
- Photonics Laboratory , ETH Zürich , 8093 Zürich , Switzerland
| | - Áron Szabó
- Integrated Systems Laboratory , ETH Zürich , 8092 Zürich , Switzerland
| | | | - Eric Bonvin
- Photonics Laboratory , ETH Zürich , 8093 Zürich , Switzerland
| | - Takashi Taniguchi
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Kenji Watanabe
- National Institute for Material Science , 1-1 Namiki , Tsukuba 305-0044 , Japan
| | - Palash Bharadwaj
- Department of Electrical and Computer Engineering , Rice University , Houston , Texas 77005 , United States
| | - Mathieu Luisier
- Integrated Systems Laboratory , ETH Zürich , 8092 Zürich , Switzerland
| | - Lukas Novotny
- Photonics Laboratory , ETH Zürich , 8093 Zürich , Switzerland
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7
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Song A, Shi R, Lu H, Gao L, Li Q, Guo H, Liu Y, Zhang J, Ma Y, Tang X, Du S, Li X, Liu X, Hu YZ, Gao HJ, Luo J, Ma TB. Modeling Atomic-Scale Electrical Contact Quality Across Two-Dimensional Interfaces. NANO LETTERS 2019; 19:3654-3662. [PMID: 31088050 DOI: 10.1021/acs.nanolett.9b00695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Contacting interfaces with physical isolation and weak interactions usually act as barriers for electrical conduction. The electrical contact conductance across interfaces has long been correlated with the true contact area or the "contact quantity". Much of the physical understanding of the interfacial electrical contact quality was primarily based on Landauer's theory or Richardson formulation. However, a quantitative model directly connecting contact conductance to interfacial atomistic structures still remains absent. Here, we measure the atomic-scale local electrical contact conductance instead of local electronic surface states in graphene/Ru(0001) superstructure, via atomically resolved conductive atomic force microscopy. By defining the "quality" of individual atom-atom contact as the carrier tunneling probability along the interatomic electron transport pathways, we establish a relationship between the atomic-scale contact quality and local interfacial atomistic structure. This real-space model unravels the atomic-level spatial modulation of contact conductance, and the twist angle-dependent interlayer conductance between misoriented graphene layers.
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Affiliation(s)
- Aisheng Song
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Ruoyu Shi
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Hongliang Lu
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Lei Gao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Qunyang Li
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
- AML, CNMM, School of Aerospace Engineering , Tsinghua University , Beijing 100084 , China
| | - Hui Guo
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Yanmin Liu
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Jie Zhang
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Yuan Ma
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology , University of Science and Technology Beijing , Beijing 100083 , China
| | - Xin Tang
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Shixuan Du
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Xin Li
- Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering , Beijing Institute of Technology , Beijing 100081 , China
| | - Xiao Liu
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Yuan-Zhong Hu
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Hong-Jun Gao
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Jianbin Luo
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
| | - Tian-Bao Ma
- State Key Laboratory of Tribology , Tsinghua University , Beijing 100084 , China
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8
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Gao Z, Zhou Z, Tománek D. Degenerately Doped Transition Metal Dichalcogenides as Ohmic Homojunction Contacts to Transition Metal Dichalcogenide Semiconductors. ACS NANO 2019; 13:5103-5111. [PMID: 31038922 DOI: 10.1021/acsnano.8b08190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In search of an improved strategy to form low-resistance contacts to MoS2 and related semiconducting transition metal dichalcogenides, we use ab initio density functional electronic structure calculations in order to determine the equilibrium geometry and electronic structure of MoO3/MoS2 and MoO2/MoS2 bilayers. Our results indicate that, besides a rigid band shift associated with charge transfer, the presence of molybdenum oxide modifies the electronic structure of MoS2 very little. We find that the charge transfer in the bilayer provides a sufficient degree of hole doping to MoS2, resulting in a highly transparent contact region.
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Affiliation(s)
- Zhibin Gao
- Physics and Astronomy Department , Michigan State University , East Lansing , Michigan 48824 , United States
- Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering , Tongji University , 200092 Shanghai , People's Republic of China
| | - Zhixian Zhou
- Physics and Astronomy Department , Wayne State University , Detroit , Michigan 48201 , United States
| | - David Tománek
- Physics and Astronomy Department , Michigan State University , East Lansing , Michigan 48824 , United States
- Mandelstam Institute for Theoretical Physics and School of Physics , University of the Witwatersrand , 2050 Johannesburg , South Africa
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9
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Zhang Z, Gong Y, Zou X, Liu P, Yang P, Shi J, Zhao L, Zhang Q, Gu L, Zhang Y. Epitaxial Growth of Two-Dimensional Metal-Semiconductor Transition-Metal Dichalcogenide Vertical Stacks (VSe 2/MX 2) and Their Band Alignments. ACS NANO 2019; 13:885-893. [PMID: 30586285 DOI: 10.1021/acsnano.8b08677] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two-dimensional (2D) metal-semiconductor transition-metal dichalcogenide (TMDC) vertical heterostructures play a crucial role in device engineering and contact tuning fields, while their direct integration still challenging. Herein, a robust epitaxial growth method is designed to construct multiple lattice-matched 2D metal-semiconductor TMDC vertical stacks (VSe2/MX2, M: Mo, W; X: S, Se) by a two-step chemical vapor deposition method. Intriguingly, the metallic VSe2 preferred to nucleate and extend from the energy-favorable edge site of the semiconducting MX2 underlayer to form VSe2/MX2 vertical heterostructures. This growth behavior was also confirmed by density functional theory calculations of the initial adsorption of VSe2 adatoms. In particular, the formation of Schottky-diode or Ohmic contact-type band alignments was detected for the stacks between VSe2 and p-type WSe2 or n-type MoSe2, respectively. This work hereby provides insights into the direct integration, band-alignment engineering, and potential applications of such 2D metal-semiconductor stacks in next-generation electronics, optoelectronic devices, and energy-related fields.
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Affiliation(s)
- Zhepeng Zhang
- Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
| | - Yue Gong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Xiaolong Zou
- Tsinghua-Berkeley Shenzhen Institute (TBSI) , Tsinghua University , Shenzhen 518055 , P. R. China
| | - Porun Liu
- Centre for Clean Environment and Energy , Griffith University , Gold Coast 4222 , Australia
| | - Pengfei Yang
- Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
| | - Jianping Shi
- Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
| | - Liyun Zhao
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
| | - Qing Zhang
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , P. R. China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Yanfeng Zhang
- Center for Nanochemistry (CNC), Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Academy for Advanced Interdisciplinary Studies , Peking University , Beijing 100871 , P. R. China
- Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , P. R. China
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10
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Zhou H, Zhao Y, Zhu H. Dielectric Environment-Robust Ultrafast Charge Transfer Between Two Atomic Layers. J Phys Chem Lett 2019; 10:150-155. [PMID: 30582821 DOI: 10.1021/acs.jpclett.8b03596] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding electron transfer across two-dimensional (2D) van der Waals (vdW) interfaces especially the effect of dielectric environment not only contributes to the rational design of high performance optoelectronic and photo/electrocatalytic devices but also unravels the nature of charge motion. Herein, we investigated the electron transfer process between two atomic thin layered materials coupled by vdW force at ultimate proximity. Despite their susceptible electronic properties, we show electron transfer at 2D vdW interface is robust and ultrafast (∼30 fs), regardless of the surrounding dielectrics and solvents. Considering the static energy landscape and dynamic nuclear rearrangements, our result suggests the electronic coupling at 2D vdW heterointerfaces is sufficiently strong such that electron transfers adiabatically in a barrierless and ultrafast manner where energetics and solvent relaxation are not that relevant. The robust ultrafast electron transfer against the variation of dielectric environment is highly encouraging for 2D optoelectronic and photo/electrocatalytic devices.
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Affiliation(s)
- Hongzhi Zhou
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry , Zhejiang University , Hangzhou , Zhejiang 310027 , China
| | - Yida Zhao
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry , Zhejiang University , Hangzhou , Zhejiang 310027 , China
| | - Haiming Zhu
- Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry , Zhejiang University , Hangzhou , Zhejiang 310027 , China
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11
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Choe DH, West D, Zhang S. Band Alignment and the Built-in Potential of Solids. PHYSICAL REVIEW LETTERS 2018; 121:196802. [PMID: 30468617 DOI: 10.1103/physrevlett.121.196802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 07/16/2018] [Indexed: 06/09/2023]
Abstract
The built-in potential is of central importance to the understanding of many interfacial phenomena because it determines the band alignment at the interface. Despite its importance, its exact sign and magnitude have generally been recognized as ill-defined quantities for more than half a century. Here, we provide a common energy reference of bulk matter which leads to an unambiguous definition of the built-in potential and innate (i.e., bulk) band alignment. Further, we find that the built-in potential is explicitly determined by the bulk properties of the constituent materials when the system is in electronic equilibrium, while the interface plays a role only in the absence of equilibrium. Our quantitative theory enables a unified description of a variety of important properties of interfaces, ranging from work functions to Schottky barriers in electronic devices.
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Affiliation(s)
- Duk-Hyun Choe
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Damien West
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - Shengbai Zhang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Beijing Computational Science Research Center, 10 East Xibeiwang Road, Beijing 100193, China
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12
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Seo J, Hwang KJ, Baik SI, Lee S, Cho B, Jo E, Choi M, Hahm MG, Kim YJ. Three-Dimensional Atomistic Tomography of W-Based Alloyed Two-Dimensional Transition Metal Dichalcogenides. ACS APPLIED MATERIALS & INTERFACES 2018; 10:30640-30648. [PMID: 30117322 DOI: 10.1021/acsami.8b09604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Increased interest in two-dimensional (2D) materials and heterostructures for use as components of electrical devices has led to the use of an atomically mixed phase between semiconducting and metallic transition metal dichalcogenides that exhibited enhanced interfacial characteristics. To understand the lattice structure and properties of 2D materials on the atomic scale, diverse characterization methods such as Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy (XPS) have been applied. However, determination of the exact chemical distribution, which is a critical factor for the interfacial layer, was hindered by limitations of these typical methods. In this work, atom-probe tomography (APT) was introduced for the first time to analyze the three-dimensional atomic distribution and composition variation of the atomic-scale multilayered alloy structure W xNb(1- x)Se2. Composition profiles and theoretical calculations for each atom demonstrated the reaction kinetics and stoichiometric inhomogeneity of the W xNb(1- x)Se2 layer. The role of the intermediate layer was investigated by fabrication of a WSe2-based field-effect transistor. Introduction of W xNb(1- x)Se2 between metallic NbSe2 and semiconducting WSe2 layers resulted in improved charge transport with lowering of the contact barrier.
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Affiliation(s)
- Juyeon Seo
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Kyo-Jin Hwang
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Sung-Il Baik
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
- Northwestern University Center for Atom-Probe Tomography (NUCAPT) , Evanston , Illinois 60208 , United States
| | - Suryeon Lee
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Byungjin Cho
- Department of Advanced Materials Engineering , Chungbuk National University , 1 Chungdae-ro , Seowon-gu, Cheongju , Chungbuk 28644 , Republic of Korea
| | - Euihyun Jo
- Department of Physics , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Minseok Choi
- Department of Physics , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Myung Gwan Hahm
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
| | - Yoon-Jun Kim
- Department of Materials Science and Engineering , Inha University , 100 Inha-ro , Michuhol-gu, Incheon 22212 , Republic of Korea
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13
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Wu MJ, Wu JZ, Zhang J, Chen H, Zhou JZ, Qian GR, Xu ZP, Du Z, Rao QL. A review on fabricating heterostructures from layered double hydroxides for enhanced photocatalytic activities. Catal Sci Technol 2018. [DOI: 10.1039/c7cy02314f] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
LDH is a controllable 2D material for fabricating heterostructures with another semiconductor.
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Affiliation(s)
- M. J. Wu
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - J. Z. Wu
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - J. Zhang
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - H. Chen
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - J. Z. Zhou
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - G. R. Qian
- SHU Center of Green Urban Mining & Industry Ecology
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- P. R. China
| | - Z. P. Xu
- ARC Centre of Excellence for Functional Nanomaterials
- Australian Institute for Bioengineering and Nanotechnology
- The University of Queensland
- Brisbane
- Australia
| | - Z. Du
- National Supercomputing Center in Shenzhen
- Guangdong
- P. R. China
| | - Q. L. Rao
- National Supercomputing Center in Shenzhen
- Guangdong
- P. R. China
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14
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Lv X, Wei W, Zhao P, Li J, Huang B, Dai Y. Tunable Schottky contacts in MSe2/NbSe2 (M = Mo and W) heterostructures and promising application potential in field-effect transistors. Phys Chem Chem Phys 2018; 20:1897-1903. [DOI: 10.1039/c7cp07546d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MSe2/NbSe2 (M = Mo and W) heterostructures exhibit low and tunable Schottky barriers, indicating promising application potential in field-effect transistors.
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Affiliation(s)
- Xingshuai Lv
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
| | - Wei Wei
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
| | - Pei Zhao
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
| | - Jinjin Li
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
| | - Baibiao Huang
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
| | - Ying Dai
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- 250100 Jinan
- P. R. China
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15
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Ma C, Liang L, Xiao Z, Puretzky AA, Hong K, Lu W, Meunier V, Bernholc J, Li AP. Seamless Staircase Electrical Contact to Semiconducting Graphene Nanoribbons. NANO LETTERS 2017; 17:6241-6247. [PMID: 28876939 DOI: 10.1021/acs.nanolett.7b02938] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Electrical contact to low-dimensional (low-D) materials is a key to their electronic applications. Traditional metal contacts to low-D semiconductors typically create gap states that can pin the Fermi level (EF). However, low-D metals possessing a limited density of states at EF can enable gate-tunable work functions and contact barriers. Moreover, a seamless contact with native bonds at the interface, without localized interfacial states, can serve as an optimal electrode. To realize such a seamless contact, one needs to develop atomically precise heterojunctions from the atom up. Here, we demonstrate an all-carbon staircase contact to ultranarrow armchair graphene nanoribbons (aGNRs). The coherent heterostructures of width-variable aGNRs, consisting of 7, 14, 21, and up to 56 carbon atoms across the width, are synthesized by a surface-assisted self-assembly process with a single molecular precursor. The aGNRs exhibit characteristic vibrational modes in Raman spectroscopy. A combined scanning tunneling microscopy and density functional theory study reveals the native covalent-bond nature and quasi-metallic contact characteristics of the interfaces. Our electronic measurements of such seamless GNR staircase constitute a promising first step toward making low resistance contacts.
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Affiliation(s)
- Chuanxu Ma
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Liangbo Liang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Zhongcan Xiao
- Department of Physics, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Alexander A Puretzky
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Kunlun Hong
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Wenchang Lu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Physics, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - J Bernholc
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
- Department of Physics, North Carolina State University , Raleigh, North Carolina 27695, United States
| | - An-Ping Li
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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16
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Wang Q, Deng B, Shi X. A new insight for ohmic contacts to MoS2: by tuning MoS2 affinity energies but not metal work-functions. Phys Chem Chem Phys 2017; 19:26151-26157. [DOI: 10.1039/c7cp05109c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have recently attracted tremendous interest for fundamental studies and applications.
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Affiliation(s)
- Qian Wang
- Harbin Institute of Technology
- Harbin 150080
- China
- Department of Physics
- South University of Science and Technology of China
| | - Bei Deng
- Department of Physics
- South University of Science and Technology of China
- Shenzhen 518055
- China
| | - Xingqiang Shi
- Department of Physics
- South University of Science and Technology of China
- Shenzhen 518055
- China
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