Effects of sputtering pressure and oxygen partial pressure on amorphous Ga2O3 film-based solar-blind ultraviolet photodetectors

Abstract

The coupling of Ga2O3 film with Si substrate is in favor of the development of high integration of Ga2O3-based UV photodetector. However, it is difficult in growing the high-quality crystalline Ga2O3 due to the high temperature and uncontrol growth process. In this work, the amorphous Ga2O3 (a-Ga2O3) films are deposited on Si substrates through tailoring the sputtering pressure and oxygen partial pressure to fabricate solar blind UV detectors. The results reveal that the high sputtering pressure and non-oxygen condition increase the oxygen vacancy concentration of a-Ga2O3 films. The existence of oxygen vacancy is beneficial to enhancing the internal gain of as-grown a-Ga2O3 films under UV light illumination. The UV photodetector based on the a-Ga2O3 film grown under 100 %Ar atmosphere at 20 mTorr exhibits high photodetection performances of responsivity, external quantum efficiency, and detectivity up to 2470 mA/W, 1204.7 %, and 2.55 × 1012 cm HZ1/2 W−1 under 254 nm @30 V, respectively. Alternatively, this UV photodetector hosts a rapid photo-response speed of rise time, τr and fall time, τd of 0.08 s and 0.157 s, respectively. This work offers a promising strategy to fabricate the a-Ga2O3-based solar blind UV detector with high photodetection performance, facile batch production and high integration with other electronics.