Arrayed van der Waals Vertical Heterostructures Based on 2D GaSe Grown by Molecular Beam Epitaxy.
Vertically stacking two-dimensional (2D) materials can enable the design of novel electronic and optoelectronic devices and realize complex functionality. However, the fabrication of such artificial heterostructures on a wafer scale with an atomically sharp interface poses an unprecedented challenge. Here, we demonstrate a convenient and controllable approach for the production of wafer-scale 2D GaSe thin films by molecular beam epitaxy. In situ reflection high-energy electron diffraction oscillations and Raman spectroscopy reveal a layer-by-layer van der Waals epitaxial growth mode. Highly efficient photodetector arrays were fabricated, based on few-layer GaSe on Si. These photodiodes show steady rectifying characteristics and a high external quantum efficiency of 23.6%. The resultant photoresponse is super-fast and robust, with a response time of 60 μs. Importantly, the device shows no sign of degradation after 1 million cycles of operation. We also carried out numerical simulations to understand the underlying device working principles. Our study establishes a new approach to produce controllable, robust, and large-area 2D heterostructures and presents a crucial step for further practical applications.
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Xiang
X
Yuan
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Lei
L
Tang
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Shanshan
S
Liu
§National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
Peng
P
Wang
∥Materials Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
Zhigang
Z
Chen
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Cheng
C
Zhang
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Yanwen
Y
Liu
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Weiyi
W
Wang
∥Materials Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
Yichao
Y
Zou
§National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
Cong
C
Liu
§National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
Nan
N
Guo
∥Materials Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.|⊥Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072, Australia.
Jin
J
Zou
#State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 200433, China.
Peng
P
Zhou
§National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China.
Weida
W
Hu
†State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.|‡Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China.
Faxian
F
Xiu
2D materials; GaSe; molecular beam epitaxy; p-n junctions; photodiodes; van der Waals heterostructure