High detectivity and fast response avalanche photodetector based on GaSe/PtSe2 p–n junction

Abstract

Heterojunction photodetectors based on 2D materials are a promising geometry to acquire broadband photodetection with combination of wide-bandgap and narrow bandgap functional materials. But the interface condition of the heterojunction is difficult to control due to the inevitable introduction of air bubbles and wrinkles. In this paper, a synthesis method merging exfoliation and CVD is reported to fabricate photodetectors of the GaSe/PtSe2 heterojunction. The devices present the highest responsivity and detectivity of about 1.7 A/W and 3.51 × 1012 Jones at a −10 V bias under the avalanche mode, respectively. Also, a fast response time could be obtained around 20 μs. In addition, the photodetector exhibits a clear photovoltaic effect, which can work in a self-powered mode.