Polarization-optimized AlGaN-based p-i-n avalanche photodiodes with double-barrier heterostructures for high-responsivity UV detection

An AlGaN-based p-i-n ultraviolet avalanche photodiode (APD) with double-barrier heterojunctions is proposed in this work. The polarization electric field formed by the heterojunction can significantly enhance the electric field intensity in the intrinsic layer, enabling the designed structure to exhibit superior photoelectric performance. On this basis, both conventional and designed APD structures were experimentally fabricated using metal-organic chemical vapor deposition. A current–voltage (I–V) characteristic measurement system was established to evaluate the photoelectric performance of the APDs with different structures. The measurement results demonstrate that at a reverse bias of 20 V, the designed APD demonstrates approximately 17% higher peak responsivity and 6% greater external quantum efficiency compared to the conventional APD structure.