Oxygen-vacancy-dependent high-performance α-Ga2O3 nanorods photoelectrochemical deep UV photodetectors

Ga2O3 is a good candidate for deep ultraviolet photodetectors due to its wide-bandgap, good chemical, and thermal stability. Ga2O3-based photoelectrochemical (PEC) photodetectors attract increasing attention due to the simple fabrication and self-powered capability, but the corresponding photoresponse is still inferior. In this paper, the oxygen vacancy (V-o) engineering towards alpha-Ga2O3 was proposed to obtain high-performance PEC photodetectors. The alpha-Ga2O3 nanorods were synthesized by a simple hydrothermal method with an annealing process. The final samples were named as Ga2O3-400, Ga2O3-500, and Ga2O3-600 for annealing at 400 celcius, 500 celcius, and 600 celcius, respectively. Different annealing temperatures lead to different V-o concentrations in the alpha-Ga2O3 nanorods. The responsivity is 101.5 mA W-1 for Ga2O3-400 nanorod film-based PEC photodetectors under 254 nm illumination, which is 1.4 and 4.0 times higher than those of Ga2O3-500 and Ga2O3-600 nanorod film-based PEC photodetectors, respectively. The photoresponse of alpha-Ga2O3 nanorod film-based PEC photodetectors strongly depends on the V-o concentration and high V-o concentration accelerates the interfacial carrier transfer of Ga2O3-400, enhancing the photoresponse of Ga2O3-400 nanorod film-based PEC photodetectors. Furthermore, the alpha-Ga2O3 nanorod film-based PEC photodetectors have good multicycle, long-term stability, and repeatability. Our result shows that alpha-Ga2O3 nanorods have promising applications in deep UV photodetectors.

Automated summary

This paper investigates the effect of oxygen vacancy (V-o) engineering on α-Ga2O3 and synthesizes α-Ga2O3 nanorods with different V-o concentrations through annealing at different temperatures. The results show that Ga2O3-400 nanorod film-based photoelectrochemical (PEC) photodetectors exhibit higher responsivity under 254 nm illumination, and they also demonstrate good multicycle stability, long-term stability, and repeatability. This indicates the promising applications of α-Ga2O3 nanorods in deep ultraviolet (UV) photodetectors.