Van der Waals epitaxial growth of vertically stacked Sb2Te3 /MoS2 p-n heterojunctions for high performance optoelectronics

Two dimensional (2D) p-n heterostructures are demonstrated to be promising candidates for future integrated electronics and optoelectronics ascribing to their unique physical, optical and electrical properties. In this work, for the first time, we report the successful synthesis of high quality vertically stacked Sb2Te3/MoS2 heterostructures via van der Waals (vdW) epitaxial growth. Due to the p-type nature of Sb2Te3 and n-type nature of MoS2, the constructed Sb2Te3/MoS2 heterostructure-based devices can function as high performance rectifying diodes, and be further used as photodetectors and photovoltaics. As a result, the achieved p-n heterojunctions exhibit ultra-high current rectification ratio up to 10(6) and typical photon-to-electron conversion efficiency reaching 4.5%, both of which are much higher than all the previously reported 2D vdW heterojunctions grown by vapor deposition routes. Moreover, remarkable photoresponsivity (330 A/W) and fast photoresponse speed (< 500 mu s) are achieved, which also represent the highest values reported so far in similar systems. Combing the excellent electrical and optoelectrical properties, the achieved Sb2Te3/MoS2 heterostructures may find broad applications in future integrated electronics and optoelectronics devices and systems.