Effect of Oxygen Plasma on ?-Ga2O3 Deep Ultraviolet Photodetectors Fabricated by Plasma-Assisted Pulsed Laser Deposition

Abstract

We fabricated metal-semiconductor-metal-structured fi-Ga2O3 photodetectors using a plasma-assisted pulsed laser deposition system with various oxygen plasma radio frequency (RF) powers ranging from 0 to 100 W. All optoelectronic properties of the material were enhanced as the RF power increased. fi-Ga2O3 photodetector with RF power of 100 W showed the best optoelectronic characteristics, such as photoresponsivity of 0.39 A/W, external quantum efficiency of 192.61%, and detectivity of 9.09 x 1013 cm Hz1/2/W. In addition, photo-switching analysis revealed the fastest photoresponse speeds (1.46 and 0.21 s) for on/ off switching. These results originate from the decrease in the oxygen vacancy defect concentration in the fi-Ga2O3 films by the oxygen RF power. Our results suggest that fi-Ga2O3 photodetectors fabricated with oxygen plasma can optimize and improve the photodetection performance and can be applied for future deep ultraviolet detectors.