Photoswitching effect of graphene photogated diodes with interfacial layers

Abstract

Graphene/semiconductor heterojunction-based photodetectors are expected to achieve high performance in various wavelength regions. Graphene photogated diodes (GPDs) based on such heterojunctions are promising for the fabrication of high-performance photodetectors, which cannot be achieved using conventional technologies. However, their action mechanism has not yet been theoretically demonstrated. In this study, we investigated the mechanism of GPDs with and without an interfacial layer. We demonstrated that the thin interfacial native oxide layer is responsible for the reduction in the Fermi level induced by photogating, which is similar to “photoswitching.” This effect induces an extraordinarily large output current in GPDs with a barrier layer.