High-performance asymmetric electrodes photodiode based on Sb/WSe2 heterostructure.

Two-dimensional (2D) van der Waals (vdWs) metal-semiconductor heterostructures with atomically sharp interface and matched work functions have recently attracted great attention due to their unique electronic and optoelectronic properties. Here we report the vapor phase epitaxial growth of large-scale vertical Sb/WSe₂ metal-semiconductor vdWs heterostructures with uniform stacking orientation. Compared with the growth on SiO₂/Si substrate, the thickness of Sb nanosheet on WSe₂ can be reduced effectively to monolayer. We construct Sb-WSe₂-Au asymmetric electrodes photodiode based on the Sb/WSe₂ heterostructures. Electrical transport measurements indicate that the photodiode show obvious rectifying effect. Optoelectronic characterizations show prominent photoresponse with a high photoresposivity of 364 mA/W, a fast response time of less than 8 ms, a large open-circuit voltage of 0.27 V and a maximum electrical power output of 0.11 nW. The direct growth of high-quality metal-semiconductor vdWs heterostructures may open up new realms in 2D functional electronics and optoelectronics. [ABSTRACT FROM AUTHOR]