High Detectivity of Metal–Semiconductor–Metal Ga₂O₃ Solar-Blind Photodetector Through Thickness-Regulated Gain

Detectivity is the most key parameter in weak-signal photodetection, which depends on high photoresponse and low noise simultaneously. In this work, metal–semiconductor–metal solar-blind UV detectors with internal gain were fabricated based on high resistant and a certain oxygen vacancy density Ga ₂ O ₃ thin films. Electrical measurements and electric field simulation indicated that thickening the active layer is helpful for high responsivity. The gain is dominated by the tunneling effect in high electric field under the electrodes. A high photoresponse of 371 A/W and a normalized detectivity up to $6.6\times10$ ¹⁶ Jones were obtained.