Optimizing the performance of a β-Ga2O3 solar-blind UV photodetector by compromising between photoabsorption and electric field distribution

Abstract

Deep ultraviolet solar blind photodetectors based on an ultra-wide band gap semiconductor of β-Ga2O3 have attracted much attention for their potential applications, e.g., missile tracking, space communication, and ozone hole monitoring. As the active layer of photodetectors, the thickness of β-Ga2O3 films plays an important role in the photoelectric performance of the photodetector because it affects the ultraviolet light photoabsorption and the electric field distribution. Highly oriented (2¯01) direction β-Ga2O3 thin films with different thickness (90 nm-540 nm) were grown on (0001) sapphire substrates using radio frequency magnetron sputtering with a substrate temperature of 750 °C. Based on the different thicknesses of β-Ga2O3 thin films, the MSM structure photodetectors were fabricated and the photoelectric performances were investigated. A photodetector with 303 nm thick thin films has the highest light-to-dark current ratio (Ilight/Idark≈16250) and exhibits the best solar-blind photoelectric performance.