CuInO2 epitaxial thin films on epi-GaN wafer: Fabrication and solar-blind photodetector

High-quality p-type CuInO2 epitaxial thin films with a bandgap of similar to 3.99 eV were grown on epitaxial GaN (001) (epi-GaN) wafers by using pulsed laser deposition technology. At a constant growth temperature of 750 degrees C, the quality of the CuInO2 thin film increases with the decrease in oxygen pressure within the range of 0.09-1 Pa. For the single crystal film obtained at 0.09 Pa, the epitaxial relationship between the film and the substrate is determined to be CuInO2 (001) parallel to GaN (001) with CuInO2 < 1 0 0 > parallel to GaN [1 0 0]. The self-powered ultraviolet photodetector prepared based on the highest quality film shows high photoresponsivity 0.31 mA/W and fast response speed (rise time: 0.34 s, decay time: 0.34 s) at zero voltage under 254-nm UV-light, meaning good solar-blind photoresponsivity.

Automated summary

In this study, high-quality p-type CuInO2 epitaxial thin films were successfully grown on GaN wafers using pulsed laser deposition technology. The films exhibited a bandgap of around 3.99 eV. The quality of the CuInO2 thin film improved with decreasing oxygen pressure, and the highest quality film demonstrated high photoresponsivity and fast response speed in a solar-blind wavelength.