Deep ultraviolet photodiodes based on the β-Ga2O3/GaN heterojunction

Abstract

A deep ultraviolet (UV) photodiode was fabricated using a heterojunction between β-Ga2O3 and GaN, and its UV sensitivity was investigated. A thin β-Ga2O3 layer was prepared on p-type GaN template substrate by gallium evaporation in oxygen plasma. The β-Ga2O3 layer had a (−201)-oriented crystal structure on (001) GaN. A device based on the β-Ga2O3/GaN heterojunction exhibited good rectifying properties. Under reverse bias, the current increased linearly with an increase in the deep-UV light intensity. The responsivity of the photodiode was highest under deep-UV light below a wavelength of 240nm. The response time of the photodiode to deep-UV light was in the order of sub-milliseconds.