Research of nanopore structure of Ga ₂ O ₃ film in MOCVD for improving the performance of UV photoresponse

Abstract

Using the mechanism of self-reactive etching between Ga and Ga₂O₃, Ga₂O₃ nanopore films were fabricated. The self-reactive etching effects based on as-grown and annealed Ga₂O₃ films by metal organic chemical vapor deposition were compared. It was found that the nanopore film based on as-grown Ga₂O₃ film has a uniform size, high density and a small diameter. Ultraviolet-visible light reflection spectra and transmission spectra show that the nanopore film could effectively reduce the reflectivity of light and enhance the light absorption. Based on the as-grown Ga₂O₃ film and its nanopore film, metal-semiconductor-metal structure solar blind ultraviolet photodetectors (PD) were fabricated. Under 5 V bias, the light-dark current ratio of the nanopore film PD is about 2.5 × 10² times that of the film PD, the peak responsivity of the nanopore film PD is about 49 times that of the film PD. The rejection ratio is 4.6 × 10³, about 1.15 × 10² times that of the film PD. The nanopore structure effectively increases the surface-volume ratio of film. The photoelectric detection performance and response performance of the nanopore film PD could be significantly enhanced.