Synthesis of 2D MoS2(1- x)Se2 x semiconductor alloy by chemical vapor deposition

Wenwen Yao; Zhilin Kang; Jiajun Deng; Yan Chen; Qian Song; Xun Lei Ding; Fangchao Lu; Wenjie Wang

doi:10.1039/d0ra07776c

Synthesis of 2D MoS_{2(1- x)}Se_{2 x} semiconductor alloy by chemical vapor deposition

RSC Adv. 2020 Nov 20;10(69):42172-42177. doi: 10.1039/d0ra07776c. eCollection 2020 Nov 17.

Authors

Wenwen Yao^{1

2}, Zhilin Kang¹, Jiajun Deng^{1

2}, Yan Chen^{1

2}, Qian Song¹, Xun Lei Ding^{1

2}, Fangchao Lu^{1

2}, Wenjie Wang^{1

2}

Affiliations

¹ School of Mathematics and Physics, North China Electric Power University Beijing 102206 China wwj2008@ncedu.edu.cn.
² Institute of Clusters and Low Dimensionals, North China Electric Power University Beijing 102206 China.

Abstract

Alloying/doping in two-dimensional (2D) materials is emerging as an increasingly important strategy due to the wide-range bandgap tunability and versatility of these materials. Monolayer 2D transition metal dichalcogenide (TMD) alloy has been investigated both theoretically and experimentally in recent years. Here, we synthesized a bilayer MoS_2(1-x)Se_2x semiconductor alloy via the chemical-vapor deposition technique. The as-grown triangular MoS_2(1-x)Se_2x flakes with size of roughly 10 μm were observed by optical microscope and scanning electron microscope (SEM). The 1.4-1.9 nm thickness of the samples, as measured by AFM, means that bilayer MoS_2(1-x)Se_2x alloys were grown. The characteristic Raman modes related to Mo-S and Mo-Se vibrations were observed in the Raman spectrum. Two emission peaks were respectively found, corresponding to the A and B excitons in the photoluminescence (PL) spectrum. XPS measurements confirmed the Se doping of the alloy. The first-principles calculation results show a contraction of the band gap value with the increase of Se doping in the MoS₂ lattice. Compared with monolayer MoS_2(1-x)Se_2x alloy, the band bending effect is more obvious, and the bilayer MoS_2(1-x)Se_2x alloy still shows the direct band gap luminescence characteristic, which has certain guiding significance for the growth of two-dimensional materials and for device preparation.