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Ogura H, Kawasaki S, Liu Z, Endo T, Maruyama M, Gao Y, Nakanishi Y, Lim HE, Yanagi K, Irisawa T, Ueno K, Okada S, Nagashio K, Miyata Y. Multilayer In-Plane Heterostructures Based on Transition Metal Dichalcogenides for Advanced Electronics. ACS NANO 2023; 17:6545-6554. [PMID: 36847351 DOI: 10.1021/acsnano.2c11927] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In-plane heterostructures of transition metal dichalcogenides (TMDCs) have attracted much attention for high-performance electronic and optoelectronic devices. To date, mainly monolayer-based in-plane heterostructures have been prepared by chemical vapor deposition (CVD), and their optical and electrical properties have been investigated. However, the low dielectric properties of monolayers prevent the generation of high concentrations of thermally excited carriers from doped impurities. To solve this issue, multilayer TMDCs are a promising component for various electronic devices due to the availability of degenerate semiconductors. Here, we report the fabrication and transport properties of multilayer TMDC-based in-plane heterostructures. The multilayer in-plane heterostructures are formed through CVD growth of multilayer MoS2 from the edges of mechanically exfoliated multilayer flakes of WSe2 or NbxMo1-xS2. In addition to the in-plane heterostructures, we also confirmed the vertical growth of MoS2 on the exfoliated flakes. For the WSe2/MoS2 sample, an abrupt composition change is confirmed by cross-sectional high-angle annular dark-field scanning transmission electron microscopy. Electrical transport measurements reveal that a tunneling current flows at the NbxMo1-xS2/MoS2 in-plane heterointerface, and the band alignment is changed from a staggered gap to a broken gap by electrostatic electron doping of MoS2. The formation of a staggered gap band alignment of NbxMo1-xS2/MoS2 is also supported by first-principles calculations.
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Affiliation(s)
- Hiroto Ogura
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Seiya Kawasaki
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Zheng Liu
- Innovative Functional Materials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan
| | - Takahiko Endo
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Mina Maruyama
- Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Yanlin Gao
- Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Yusuke Nakanishi
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Hong En Lim
- Department of Chemistry, Saitama University, Saitama 338-8570, Japan
| | - Kazuhiro Yanagi
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Toshifumi Irisawa
- Device Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - Keiji Ueno
- Department of Chemistry, Saitama University, Saitama 338-8570, Japan
| | - Susumu Okada
- Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Kosuke Nagashio
- Department of Materials Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Yasumitsu Miyata
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
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Matsuyama K, Aoki R, Miura K, Fukui A, Togawa Y, Yoshimura T, Fujimura N, Kiriya D. Metallic Transport in Monolayer and Multilayer Molybdenum Disulfides by Molecular Surface Charge Transfer Doping. ACS APPLIED MATERIALS & INTERFACES 2022; 14:8163-8170. [PMID: 35107263 DOI: 10.1021/acsami.1c22156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Carrier modulation in transition-metal dichalcogenides (TMDCs) is of importance for applying electronic devices to tune their transport properties and controlling phases, including metallic to superconductivity. Although the surface charge transfer doping method has shown a strong modulation ability of the electronic structures in TMDCs and a degenerately doped state has been proposed, the details of the electronic states have not been elucidated, and this transport behavior should show a considerable thickness dependence in TMDCs. In this study, we characterize the metallic transport behavior in the monolayer and multilayer MoS2 under surface charge transfer doping with a strong electron dopant, benzyl viologen (BV) molecules. The metallic behavior transforms to an insulative state under a negative gate voltage. Consequently, metal-insulator transition (MIT) was observed in both monolayer and multilayer MoS2 correlating with the critical conductivity of order e2/h. In the multilayer case, the BV molecules strongly modulated the topmost surface layer in the bulk MoS2; the transfer characteristics suggested a crossover from a heterogeneously doped state with a doped topmost layer to doping in the deep layers caused by the variation in the gate voltage. The findings of this work will be useful for understanding the device characteristics of thin-layered materials and for applying them to the controlling phases via carrier modulation.
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Affiliation(s)
- Keigo Matsuyama
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Ryuya Aoki
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Kohei Miura
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Akito Fukui
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Yoshihiko Togawa
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Takeshi Yoshimura
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Norifumi Fujimura
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
| | - Daisuke Kiriya
- Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
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Zhao Y, Gobbi M, Hueso LE, Samorì P. Molecular Approach to Engineer Two-Dimensional Devices for CMOS and beyond-CMOS Applications. Chem Rev 2021; 122:50-131. [PMID: 34816723 DOI: 10.1021/acs.chemrev.1c00497] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two-dimensional materials (2DMs) have attracted tremendous research interest over the last two decades. Their unique optical, electronic, thermal, and mechanical properties make 2DMs key building blocks for the fabrication of novel complementary metal-oxide-semiconductor (CMOS) and beyond-CMOS devices. Major advances in device functionality and performance have been made by the covalent or noncovalent functionalization of 2DMs with molecules: while the molecular coating of metal electrodes and dielectrics allows for more efficient charge injection and transport through the 2DMs, the combination of dynamic molecular systems, capable to respond to external stimuli, with 2DMs makes it possible to generate hybrid systems possessing new properties by realizing stimuli-responsive functional devices and thereby enabling functional diversification in More-than-Moore technologies. In this review, we first introduce emerging 2DMs, various classes of (macro)molecules, and molecular switches and discuss their relevant properties. We then turn to 2DM/molecule hybrid systems and the various physical and chemical strategies used to synthesize them. Next, we discuss the use of molecules and assemblies thereof to boost the performance of 2D transistors for CMOS applications and to impart diverse functionalities in beyond-CMOS devices. Finally, we present the challenges, opportunities, and long-term perspectives in this technologically promising field.
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Affiliation(s)
- Yuda Zhao
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France.,School of Micro-Nano Electronics, ZJU-Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, 310027 Hangzhou, People's Republic of China
| | - Marco Gobbi
- Centro de Fisica de Materiales (CSIC-UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 Donostia-San Sebastián, Spain.,CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Luis E Hueso
- CIC nanoGUNE, E-20018 Donostia-San Sebastian, Basque Country, Spain.,IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Paolo Samorì
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000 Strasbourg, France
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