Polarization-sensitive self-powered MoS2/a-GaN heterojunction photodetectors for ultraviolet polarized imaging

Abstract

Polarization-sensitive ultraviolet (UV) photodetectors have attracted significant interest due to the broad applications in UV polarized imaging. However, the conventional UV photodetectors to realize polarization-sensitive properties require integrated filters and polarizers, which increase the system size and cost. In this work, self-powered polarization-sensitive UV photodetectors (PDs) with high efficiency and ultrafast response speed based on the MoS2/a-GaN heterojunction have been proposed and applied to UV polarized imaging. Benefiting from the type-I band alignment formed by MoS2/a-GaN, and the reduction of interfacial trapping effect, the PDs exhibit remarkable photovoltaic and polarization sensitivity under UV light at zero bias voltage, including a high responsivity of 15 mA/W, a specific detectivity of 4.7 × 1013 Jones, an ultrafast response speed of 4/8 ms, and a high polarization ratio of 1.5. Furthermore, the as-fabricated PDs demonstrate polarization-sensitive UV imaging. This work paves an approach for the development of high-performance polarization-sensitive UV PDs and offers a feasible way for the development of UV polarized imaging based on anisotropic materials.