title: Tunable band gap photoluminescence from atomically thin transition-metal dichalcogenide alloys.
abstract: Band gap engineering of atomically thin two-dimensional (2D) materials is the key to their applications in nanoelectronics, optoelectronics, and photonics. Here, for the first time, we demonstrate that in the 2D system, by alloying two materials with different band gaps (MoS2 and WS2), tunable band gap can be obtained in the 2D alloys (Mo(1-x)W(x)S(2) monolayers, x = 0-1). Atomic-resolution scanning transmission electron microscopy has revealed random arrangement of Mo and W atoms in the Mo(1-x)W(x)S(2) monolayer alloys. Photoluminescence characterization has shown tunable band gap emission continuously tuned from 1.82 eV (reached at x = 0.20) to 1.99 eV (reached at x = 1). Further, density functional theory calculations have been carried out to understand the composition-dependent electronic structures of Mo(1-x)W(x)S(2) monolayer alloys.
authors.affiliation: Key Laboratory of Standardization and Measurement for Nanotechnology of Chinese Academy of Sciences, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Chen
authors.forename: Jinyang
authors.initials: J
authors.lastname: Xi
authors.forename: Dumitru O
authors.initials: DO
authors.lastname: Dumcenco
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Kazu
authors.initials: K
authors.lastname: Suenaga
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Shuai
authors.forename: Ying-Sheng
authors.initials: YS
authors.lastname: Huang
authors.forename: Liming
authors.initials: L
authors.lastname: Xie