Surface plasma treatment reduces oxygen vacancies defects states to control photogenerated carriers transportation for enhanced self-powered deep UV photoelectric characteristics

Ga2O3 is an ideal wide bandgap semiconductor for deep ultraviolet photodetectors due to the suitable band gap and excellent material stability, but the inevitable escape of oxygen ions from the lattices always leaves oxygen vacancies and leads to the persistent photoconductivity effect. Plasma treatment technology can use highly chemically active plasma to modify materials' surfaces at room temperature, which is environment-friendly and low carbon. In this work, we have prepared beta-Ga2O3 films by plasma-enhanced chemical vapor deposition (PECVD) and used plasma treatment to reduce the oxygen vacancies in-situ. Whereafter, we constructed a Schottky-type photodetector to explore the effect of plasma treatment on the photoelectronic properties of beta-Ga2O3 thin film. After plasma treatment, the oxygen vacancy reduces from 44.5 % to 27.3 %, and the photocurrent of beta-Ga2O3 photodetector increases from 11 nA to 67 nA at 0 V. Furthermore, the decrease of oxygen vacancy also improves the photoresponse speed (< 0.2 s) of the photodetector. The present study provides an efficient treatment method of oxygen vacancies by plasma technology to obtain high-performance self -powered deep-ultraviolet photodetectors.