Construction of α-Ga₂O₃-ZnO heterojunction for a promoted performance applied in self-powered solar blind photodetector

Abstract

Gallium oxide-based photoelectrochemical photodetectors (PEC-PDs) have received extensive attention for their natural self-powered characteristic and detection capability in solar-blind region. In this work, ZnO nanoparticles decorated α-Ga 2 O 3 nanorods heterojunction (α-Ga 2 O 3 -ZnO) are synthesized on FTO conductive glass substrates as photoanodes for PEC-PDs. The efficient regulation of performance for α-Ga 2 O 3 -ZnO heterojunction PEC-PDs is achieved by varying the ZnO nanoparticles concentration. Experimental results show that all devices exhibit self-powered solar blind detection characteristics and the performance of ZnO nanoparticles decorated devices are all better than that of pristine α-Ga 2 O 3 . When the concentration of ZnO nanoparticles reaches to a certain value, the responsivity attains the maximum value as high as 34.2 mA/W, and the response time is as low as 0.25/0.18 s. Combined with first-principles calculations, the mechanism of the improved performance is discussed in detail. The results reveal that that the contact between α-Ga 2 O 3 and ZnO can induce charges transfer, which constitutes a built-in electric field that acts as a driving force to separate the photogenerated carriers into different sections. This process can effectively prevent the recombination of photogenerated carriers and prolong the lifetime of e – –h + , thus improve the overall detection performance finally. This work will provide meaningful guidance for the development of novel high-performance self-powered solar-blind deep-UV photodetectors.