Catalyst-Free β-Ga2O3@a-Ga2O3 Core−Shell nanorod arrays grown on Si substrate for High-performance self-powered solar-blind photoelectrochemical photodetection

Self-powered photodetectors are recognized as one of the developing trends of next-generation optoelectronic devices. Particularly, a novel photoelectrochemical (PEC) type photodetectors have attracted a great deal of attention due to the advantages of low cost and self-powered capability. Herein, we construct, for the first time, solar-blind PEC-type photodetectors based on amorphous Ga2O3-covered β-Ga2O3 (denoted as β-Ga2O3@a-Ga2O3) core−shell nanorod arrays (NRAs) synthesized on silicon substrates using a simple one-step catalyst-free CVD method. The as-fabricated self-powered solar-blind photodetector has comprehensive photodetection performance in terms of a maximum responsivity of 48.4 mA/W, a high detectivity of 8.5 × 1011 Jones as well as fast response and recovery times (tres/trec = 125/160 ms) under 254 nm illumination with a light intensity of 0.1 mW/cm2, outperforming most of the reported Ga2O3 based PEC-type devices to date. Furthermore, the device shows good multicycle stability and repeatability. Such outstanding solar-blind photodetection performance is largely attributed to the superior crystalline quality of catalyst-free grown β-Ga2O3@a-Ga2O3 core−shell NRAs and the additional built-in electric field of a-Ga2O3 and β-Ga2O3 interface. This work provides a simple and feasible route for constructing Ga2O3-based PEC-type solar-blind photodetectors with high performance, stability and low cost.