Enhanced Ultra-narrowband Fast Response Ultraviolet Photodetector based on GaN Homojunction with a Carbon-Doped Semi-insulating Intermediate Layer.

A narrowband detection photodetector (PD) serves as a rapid identifier of specific wavebands, holding immense significance in secure communication and spectral recognition. Herein, after carbon is doped into GaN, an acceptor energy level emerges in its band structure, which will compensate with donor states in GaN to reduce carrier concentration and make GaN semi-insulating, and it affected the dark current and electric field distribution of the GaN p-i-n PD. Operating at a bias of 0 V, the C-doped GaN p-i-n PD demonstrates an ultralow dark current density and a high light-to-dark current ratio compared to the undoped intrinsic i-layer GaN p-i-n PD. Moreover, the narrowband response's full width at half-maximum of the PD is only 8.11 nm and displays rapid signal feedback capabilities. Consequently, this prepared C-doped GaN p-i-n PD, which obviates the need for integrating optical filters or employing sophisticated processes, stands to be capable of accurately distinguishing UVA radiation.