High-performance solar-blind ultraviolet photodetector arrays based on two-inch ε-Ga2O3 films for imaging applications

Abstract To achieve high-quality solar-blind imaging applications based on ultrawide bandgap semiconductor photodetectors, it is crucial to fabricate highly uniform wafer-scale films. In this work, we demonstrate the fabrication of exceptionally uniform two-inch ε-Ga2O3 thin films on sapphire substrates using an off-axis pulsed laser deposition method. The two-inch ε-Ga2O3 films exhibit remarkable uniformity across key parameters, including thickness, crystalline quality, bandgap, and surface roughness, with an inhomogeneity ratio less than 5%. Additionally, these films are preferentially oriented along the (001) crystal plane. At 20 V bias, the individual ε-Ga2O3 photodetector demonstrates outstanding solar-blind ultraviolet (UV) photodetection performance, with a responsivity of 52.77 A/W at 240 nm, an external quantum efficiency of 2.7×104%, a dark current of 5.5×10-11 A and a UV–visible rejection ratio of 1.2×104. Furthermore, the 10×10 photodetector arrays fabricated on two-inch ε-Ga2O3 films exhibit highly uniform photodetection performance, with photocurrent deviations remaining within one order of magnitude and a maximum standard deviation of ~8%. High-contrast optical imaging of the letters of “NIMTE” is successfully achieved using the 10×10 photodetector array detector. This work provides valuable insights for fabricating wafer-scale uniform ε-Ga2O3 films and achieving high-quality solar-blind UV imaging applications.