Improvement of Responsivity of GaN-Based p-i-n Ultraviolet Photodetector by Inserting a Delta Doped Layer in Active Region

GaN-based homojunction p-i-n ultraviolet (UV) photodetectors (PDs) with the conventional structure and delta doped layer in the p-n interface are investigated numerically. Using the delta doped n-type layer, the PDs exhibit much higher responsivity and almost does not affect the dark current as compared to conventional one. Simulation results show that the enhancement of the carrier injection from p-type region, which is the main reason behind the improved performance of GaN-based p-i-n PDs employing the delta doping. This beneficial effect is more remarkable in situations with higher p-cap absorption, such as devices with a thickness p-cap layer or devices with a higher Aluminium composition.