Universal low-temperature Ohmic contacts for quantum transport in transition metal dichalcogenides. (22nd April 2016)

• Record Type: Journal Article
• Authors: Xu, Shuigang; Wu, Zefei; Lu, Huanhuan; Han, Yu; Long, Gen; Chen, Xiaolong; Han, Tianyi; Ye, Weiguang; Wu, Yingying; Lin, Jiangxiazi; Shen, Junying; Cai, Yuan; He, Yuheng; Zhang, Fan; Lortz, Rolf; Cheng, Chun; Wang, Ning
• Is Part Of: 2D materials. Volume 3:Number 2(2016)
• Publication Date: 2016-04-22
• Subjects: transition metal dichalcogenides -- h-BN encapsulation -- field-effect transistor -- contact resistance -- quantum oscillations; Graphene -- Periodicals; Materials science -- Periodicals; Nanostructured materials -- Periodicals; 620.115
• DOI: 10.1088/2053-1583/3/2/021007
• Languages: English
• ISSNs: 2053-1583

Abstract

Abstract: Low carrier mobility and high electrical contact resistance are two major obstacles prohibiting explorations of quantum transport in TMDCs. Here, we demonstrate an effective method to establish low-temperature Ohmic contacts in boron nitride encapsulated TMDC devices based on selective etching and conventional electron-beam evaporation of metal electrodes. This method works for most extensively studied TMDCs in recent years, including MoS2, MoSe2, WSe2, WS2, and 2H-MoTe2 . Low electrical contact resistance is achieved at 2 K. All of the few-layer TMDC devices studied show excellent performance with remarkably improved field-effect mobilities ranging from 2300 to 16 000 cm 2 V −1 s −1, as verified by the high carrier mobilities extracted from Hall effect measurements. Moreover, both high-mobility n-type and p-type TMDC channels can be realized by simply using appropriate contact metals. Prominent Shubnikov–de Haas oscillations have been observed and investigated in these high-quality TMDC devices.