title: Layer-dependent electrical and optoelectronic responses of ReSe2 nanosheet transistors.
abstract: The ability to control the appropriate layer thickness of transition metal dichalcogenides (TMDs) affords the opportunity to engineer many properties for a variety of applications in possible technological fields. Here we demonstrate that band-gap and mobility of ReSe2 nanosheet, a new member of the TMDs, increase when the layer number decreases, thus influencing the performances of ReSe2 transistors with different layers. A single-layer ReSe2 transistor shows much higher device mobility of 9.78 cm(2) V(-1) s(-1) than few-layer transistors (0.10 cm(2) V(-1) s(-1)). Moreover, a single-layer device shows high sensitivity to red light (633 nm) and has a light-improved mobility of 14.1 cm(2) V(-1) s(-1). Molecular physisorption is used as "gating" to modulate the carrier density of our single-layer transistors, resulting in a high photoresponsivity (Rλ) of 95 A W(-1) and external quantum efficiency (EQE) of 18 645% in O2 environment. This work highlights the fact that the properties of ReSe2 can be tuned in terms of the number of layers and gas molecule gating, and single-layer ReSe2 with appropriate band-gap is a promising material for future functional device applications.
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China. jbli@semi.ac.cn.
authors.forename: Shengxue
authors.initials: S
authors.lastname: Yang
authors.forename: Sefaattin
authors.initials: S
authors.lastname: Tongay
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Qu
authors.initials: Q
authors.lastname: Yue
authors.forename: Jian-Bai
authors.initials: JB
authors.lastname: Xia
authors.forename: Shun-Shen
authors.initials: SS
authors.lastname: Li
authors.forename: Jingbo
authors.initials: J
authors.lastname: Li
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei