A bipolar response deep ultraviolet photodetector for encryption and anti-interference communication based on an a-Sb2O5/a-Ga2O3 heterojunction

Abstract

The integration of positive photoconductivity (PPC) and negative photoconductivity (NPC) significantly enhances the functionality of photodetectors. Sb(V)-based oxides are gaining prominence in advanced applications due to their notably deep band edges and favorable band alignment characteristics that benefit the photoelectric interface. The deep ultraviolet photodetector based on the a-Sb₂O₅/a-Ga₂O₃ heterostructure demonstrates wavelength–voltage synergistic bipolar photocurrent switching, attributed to the carrier trapping mechanism at the interface states. This detector exhibits an NPC responsivity of 0.71 mA W⁻¹ (at 0 V, 287 nm) and a PPC responsivity of 1.05 mA W⁻¹ (at 1 V, 303 nm). Furthermore, it shows a bidirectional photocurrent with short-wavelength NPC and long-wavelength PPC at a transition voltage of 0.5 V. Based on the bidirectional photoresponse, the detector not only enhances the confidentiality of real-time communication through bipolar coding technology but also reduces the detector's bit error rate via redundant error correction through bipolar channels. The wavelength–voltage synergistically controlled bipolar response of the a-Sb₂O₅/a-Ga₂O₃ heterojunction exhibits significant potential for developing novel optical communication devices suited for specialized environments.