One ε-Ga2O3-based solar-blind Schottky photodetector emphasizing high photocurrent gain and photocurrent-intensity linearity

Abstract

The ε-Ga2O3 thin film was grown on sapphire substrate by using metalorganic chemical vapor deposition (MOCVD) method, and then was used to fabricate a deep-ultraviolet (DUV) photodetector (PD). The ε-Ga2O3 thin film shown good crystal quality and decent surface morphology. Irradiated by a 254-nm DUV light, the photodetector displayed good optoelectronic performance and high wavelength selectivity, such as photoresponsivity (R) of 175.69 A/W, detectivity (D*) of 2.46 × 1015 Jones, external quantum efficiency (EQE) of 8.6 × 104% and good photocurrent-intensity linearity, suggesting decent DUV photosensing performance. At 5 V and under illumination with light intensity of 800 μW/cm2, the photocurrent gain is as high as 859 owing to the recycling gain mechanism and delayed carrier recombination; and the photocurrent gain decreases as the incident light intensity increases because of the recombination of photogenerated carriers by the large photon flux.