Phase-Controlled Synthesis of Monolayer W1- x Rex S2 Alloy with Improved Photoresponse Performance

Zixuan Wang; Xiaoxu Zhao; Yuekun Yang; Lei Qiao; Lu Lv; Zhang Chen; Zengfeng Di; Wei Ren; Stephen J Pennycook; Jiadong Zhou; Yanfeng Gao

doi:10.1002/smll.202000852

Phase-Controlled Synthesis of Monolayer W_1- _x Re_x S₂ Alloy with Improved Photoresponse Performance

Small. 2020 May;16(20):e2000852. doi: 10.1002/smll.202000852. Epub 2020 Apr 22.

Authors

Zixuan Wang¹, Xiaoxu Zhao², Yuekun Yang³, Lei Qiao⁴, Lu Lv¹, Zhang Chen¹, Zengfeng Di³, Wei Ren⁴, Stephen J Pennycook², Jiadong Zhou⁵, Yanfeng Gao¹

Affiliations

¹ School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China.
² Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore.
³ State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China.
⁴ Department of Physics, Shanghai Key Laboratory of High Temperature Superconductors, MGI and ICQMS, Shanghai University, Shanghai, 200444, China.
⁵ School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.

PMID: 32323489
DOI: 10.1002/smll.202000852

Abstract

Tuning bandgap and phases in the ternary 2D transition metal dichalcogenides (TMDs) alloys has opened up unexpected opportunities to engineer optoelectronic properties and explore potential applications. In this work, a salt-assisted chemical deposition vapor (CVD) growth strategy is reported for the creation of high-quality monolayer W_1- _x Re_x S₂ alloys to fulfill a readily phase control from 1H to DT by changing the ratio of Re and W precursors. The structures and chemical compositions of doping alloys are confirmed by combining atomic resolution scanning transmission electron microscopy-annular dark field imaging with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy, matching well with the calculated results. The field-effect transistors (FETs) devices fabricated based on 1H-W_0.9 Re_0.1 S₂ monolayer exhibit a n-type semiconducting behavior with the mobility of 0.4 cm² V^-1 s^-1 . More importantly, the FETs show high-performance responsivity with a value of 17 µA W^-1 in air, which is superior to that of monolayer CVD-grown WS₂ . This work paves the way toward synthesizing monolayer ternary alloys with controlled phases for potential optoelectronic applications.

Keywords: W 1− xRe xS 2 alloys; chemical vapor deposition; phase transition; photoresponsivity; ternary TMDs.

Abstract

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