A field-effect approach to directly profiling the localized states in monolayer MoS2

Hao Wu; Yuan Liu; Zeyu Deng; Hung-Chieh Cheng; Dehui Li; Jian Guo; Qiyuan He; Sen Yang; Mengning Ding; Yun-Chiao Huang; Chen Wang; Yu Huang; Xiangfeng Duan

doi:10.1016/j.scib.2019.05.021

A field-effect approach to directly profiling the localized states in monolayer MoS₂

Sci Bull (Beijing). 2019 Aug 15;64(15):1049-1055. doi: 10.1016/j.scib.2019.05.021. Epub 2019 May 23.

Authors

Hao Wu¹, Yuan Liu², Zeyu Deng³, Hung-Chieh Cheng¹, Dehui Li³, Jian Guo¹, Qiyuan He³, Sen Yang¹, Mengning Ding¹, Yun-Chiao Huang¹, Chen Wang¹, Yu Huang⁴, Xiangfeng Duan⁵

Affiliations

¹ Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA.
² Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA. Electronic address: yuanliuhnu@hnu.edu.cn.
³ Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
⁴ Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA.
⁵ Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA. Electronic address: xduan@chem.ucla.edu.

PMID: 36659764
DOI: 10.1016/j.scib.2019.05.021

Abstract

A fundamental understanding of the charge transport mechanism in two-dimensional semiconductors (e.g., MoS₂) is crucial for fully exploring their potential in electronic and optoelectronic devices. By using monolayer graphene as the barrier-free contact to MoS₂, we show that the field-modulated conductivity can be used to probe the electronic structure of the localized states. A series of regularly distributed plateaus were observed in the gate-dependent transfer curves. Calculations based on the variable-range hopping theory indicate that such plateaus can be attributed to the discrete localized states near mobility edge. This method provides an effective approach to directly profiling the localized states in conduction channel with an ultrahigh resolution up to 1 meV.

Keywords: Conductivity plateau; Electronic transport; Field-effect transistor; Localized states; Two-dimensional layered materials.