Currents in Hg1-xCdxTe photodiodes

Carrier transport mechanisms in Hg1-xCdxTe (x = 0.2 divided by 0.265) photodiodes in the temperature range 70 divided by 150 K are discussed. Two major current mechanisms were included into balance equations for the p-n-junction: trap-assisted tunneling (TAT) and Shockley-Reed-Hall (SRH) generation-recombination processes. For TAT Anderson's matrix element of the impurity ionization was used and the tunneling rate characteristics were calculated in the k-p approximation with the constant barrier field. Other current mechanisms were included in consideration as additive contributions. Using donor and acceptor concentrations, trap level concentrations, trap level energy, and in-junction trap level lifetimes as fitting parameters, we obtain a relatively good agreement with the experimental data.