The photovoltaic and photoconductive photodetector based on CeSe/2D semiconductor van der Waals heterostructure

摘要

Although plenty of two-dimensional (2D) semiconductor heterostructure photodetectors have been studied, there is still a lack of systematic comparison and analysis about photovoltaic and photoconductive 2D semiconductor photodetectors. Taking advantage of the 2D semiconductor van der Waals heterostructure, this work constructs a photovoltaic (PV) GeSe/MoS_2 and a photoconductive (PC) GeSe/graphene photodetector, respectively. The PC GeSe/graphene photodetector achieves relatively higher photoresponsivity (R), where R can reach up to 10~4 AW~(-1). The PV GeSe/MoS_2 photodetector, by contrast, obtains a faster photoresponse speed. More importantly, the photoresponse properties of the PV GeSe/MoS_2 photodetector can remain constant under the reverse bias, due to the minority carrier conduction in its depletion region at this time. The different characteristics of the two type 2D photodetectors are explored in detail, which can play a guiding role in the construction of high-performance photodetectors.