Pyro-Photoelectric Effect Enhanced Dual-Mode Self-Powered ITO/ZnO:Ga Microwire/AlGaN Thin-Film Heterojuncted Ultraviolet Imaging Photodetector

Ultraviolet (UV) photodetectors have received a significant amount of attention in a variety of areas; especially, self-powered photodetectors are anticipated to address the energy-saving demand in the astronautics under the photovoltaic effect. In this work, a Ga-doped ZnO (ZnO:Ga)/Al $_{{0}.{1}}$ Ga $_{{0}.{9}}\text{N}$ (AlGaN) heterojunction is introduced for performing UV photodetector, which is enhanced by the pyro-photoelectric effect coupling of pyroelectric and photovoltaic effects. The heterojunction UV photodetector can operate in a self-powered mode with aresponsivity of 0.063 mA $\text{W}^{-{1}}$ under the illumination of $135 \mu \text{W}$ cm $^{-{2}}$ . More importantly, after pyro-photoelectric enhancement, the photocurrent is effectively increased from 13 to 45 pA. Additionally, under the illumination of $493 \mu \text{W}$ cm $^{-{2}}$ , the photo-to-dark-current ratio (PDCR) of 80 and ${{1}.{7} \times {10}}^{{4}}$ is obtained at a reverse bias of −10 V and forward bias of +10 V, respectively, indicating that the heterojunction UV photodetector can be regarded as a dual-mode photodetector since it can operate in both forward-biased photoconductive mode and reverse-biased depletion mode. Moreover, the UV photodetector exhibits a fast temporal pulsed laser response with a rising time of 0.79 ms and a decay time of 9.4 ms. In all, this work presents a novel strategy for the advancement of UV detection.