Electron irradiation of p-type mercury cadmium telluride

30 Mev electrons were used to irradiate samples of p-type Hg1-x CdxTe to study radiation induced changes in conductivity versus temperature. Samples were held below 95 K while irradiated with doses between 4 x 10 to the 13th power electrons/sg cm and 6 x 10 to the 15th power electrons/sq cm. Litle or no changes in conductivity was detected for the lower dose levels. Conductivity steadily decreased with increasing dose level, showing a 50% decline at 100 K for the maximum dose. The decrease in conductivity was smaller at higher temperatures. Approximately two hour post-irradiation temperature excursions up to 300 K, resulted in a 25% restoration of the conductivity at 100 K. The mobility of the samples, irradiated at the maximum dose level showed a 3 to 6 fold increase, while the majority carrier concentration decreased by a factor of 7 to 10 times the pre-irradiation values. All samples irradiated with dose levels above 1 x 10 to the 15 power electrons/sq cm, converted from p to n-type at 295/K, but remained p-type at 77 K. It was hypothesized that radiation induced donor defect levels in the conduction band were responsible for the reported changes. (Author)