Numerical simulation of Hg1-xCdxTe hole avalanche photodiodes

Hg_1-xCd_xTe hole-initiated avalanche diode devices(h-APD) can operate at 300K due to their wide bandgap and low dark current characteristics under high operating bias [1-4]. This paper simulates the band structure, quantum efficiency, and dark current distribution of Hg_1-xCd_xTe h-APD. The band structure simulation results show that under a high operating bias of -63.7V, the bandgap in the multiplication region is relatively narrow, and this region may generate significant dark current under a high electric field. When the Cd composition x in the Hg_1-xCd_xTe absorption region is 0.65 and the doping concentration is below 1×10¹⁵ cm^-3, an internal quantum efficiency exceeding 90% can be achieved. Under an operating bias of -63.7V, the generation–recombination (G–R) current dominates over the band tunneling (BBT) current and trap assisted tunneling (TAT) current, with a total dark current of less than 1×10^-6 A/cm². These characteristics enable the h-APD to maintain good performance at a high operating temperature of 300K and high operating bias.