Ta-Doped Ga2O3 Epitaxial Films on Porous p-GaN Substrates: Structure and Self-Powered Solar-Blind Photodetectors

Self-powered solar-blind Ga2O3-based photodetectors based on polycrystalline films rather than single-crystal films have been widely studied. In this work, Ta-doped Ga2O3 single-crystal films deposited on porous p-type GaN substrates by metal-organic chemical vapor deposition (MOCVD) were prepared as self-powered solar-blind photodetectors. As the porosity of the substrate increased, the crystal quality of the deposited film was optimized, probably resulting from the reduction of threading dislocations (TDs). The epitaxial relation between the beta-Ga2O3 single-crystal film and the GaN substrate was beta-Ga2O3 ((2) over bar 01) parallel to GaN (0001) with beta-Ga2O3 [010] parallel to GaN <2<(11)over bar>0>. Compared with the photodetector based on the beta-Ga2O3 grown on as-grown p-GaN, the detector based on the beta-Ga2O3 deposited on porous p-GaN presented fast rise/decay times (0.41 s/0.34 s) and high photoelectric responsivity (3.54 x 10(-2) A/W) at 222 nm without bias because of the electron-hole pairs separated by the in-built electric field rapidly, indicating good solar-blind response ability.

Automated summary

In this study, self-powered solar-blind photodetectors based on Ta-doped Ga2O3 single-crystal films deposited on porous p-type GaN substrates were prepared by MOCVD. The crystal quality of the deposited film was improved with the increasing porosity of the substrate, leading to better solar-blind response ability. The photodetector exhibited fast response time and high photoelectric responsivity.