Generation-recombination centers in p-type Hg1−xCdxTe

Hg1−xCdxTe photodiodes have long been thought to be limited by recombination-generation centers. The minority carrier lifetime τe in many samples of p-type Hg1−xCdxTe has been explained assuming a midgap Shockley–Read center. This modeling is not unique and does not fully characterize the center. This letter reports deep level transient spectroscopy (DLTS) data on a series of x = 0.2–0.4 p-type Hg1−xCdxTe samples. The DLTS data confirms the Shockley–Read model in that there is a commonly observed recombination center just below midgap. Another center near 3/4 Eg is also observed. Both of these centers can be important in controlling lifetime and detector performance.