title: Controllable Growth of Vertical Heterostructure GaTe(x)Se(1-x)/Si by Molecular Beam Epitaxy.
abstract: Two dimensional (2D) alloys, especially transition metal dichalcogenides, have attracted intense attention owing to their band-gap tunability and potential optoelectrical applications. Here, we report the controllable synthesis of wafer-scale, few-layer GaTexSe1-x alloys (0 ≤ x ≤ 1) by molecular beam epitaxy (MBE). We achieve a layer-by-layer growth mode with uniform distribution of Ga, Te, and Se elements across 2 in. wafers. Raman spectroscopy was carried out to explore the composition-dependent vibration frequency of phonons, which matches well with the modified random-element-isodisplacement model. Highly efficient photodiode arrays were also built by depositing few-layer GaTe0.64Se0.36 on n-type Si substrates. These p-n junctions have steady rectification characteristics with a rectifying ratio exceeding 300 and a high external quantum efficiency around 50%. We further measured more devices on MBE-grown GaTexSe1-x/Si heterostructures across the full range to explore the composition-dependent external quantum efficiency. Our study opens a new avenue for the controllable growth of 2D alloys with wafer-scale homogeneity, which is a prominent challenge in 2D material research.
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Yuan
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Materials Engineering, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Enze
authors.initials: E
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Wang
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: Materials Engineering, The University of Queensland , Brisbane, QLD 4072, Australia.
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.affiliation: National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences , Shanghai 200083, China.
authors.forename: Weida
authors.initials: W
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Surface Physics and Department of Physics and Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China.
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
keywords: GaTexSe1−x; homogeneity; molecular beam epitaxy; two-dimensional alloy