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

• We prepared (−2 0 1) oriented β-Ga2O3 thin film on p-type GaN template substrates.
• A deep UV photodiode was fabricated using a heterojunction between β-Ga2O3 and GaN.
• The photocurrent increased linearly by three orders of magnitude with increasing UV-light intensity.
• The responsivity of 0.18 A/W was obtained at a wavelength of 225 nm.
• The response time of the photodiode was in the order of sub-milliseconds.

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 (−2 0 1)-oriented crystal structure on (0 0 1) 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 240 nm. The response time of the photodiode to deep-UV light was in the order of sub-milliseconds.