Perturbed  angular correlation was used to study interactions between 111In and native defects and impurities. This technique exploited the quadrupole interaction of 111In with local electric field gradients in order to characterize the local environment of this donor dopant. It was observed that, when In was diffused into bulk or thin-film samples of Hg0.79Cd0.21Te and Hg0.7Cd0.3Te at 350C and the sample was slowly cooled, the In atoms occupied sites with near-cubic symmetry. This was presumably the substitutional metal site. However, when the sample was quenched, a fraction of the In was incorporated into defects which were characterized by quadrupole interaction strengths of 83 and 92MHz, and an asymmetry of 0.08. These defects were attributed to the trapping of a metal vacancy at a next-nearest neighbor site to the In atom. The introduction of H, by boiling samples in distilled water for more than 4h, eliminated the previously observed perturbed angular correlation signals, and created defects which were characterized by quadrupole interaction strengths of 35 and 43MHz, and an asymmetry of less than 0.1. These defects were attributed to the decoration of an In-VHg complex by a H atom. Hall-effect measurements showed that hydrogenation increased the hole concentration in p-type quenched samples, and even converted n-type In-doped samples to p-type. A possible model was suggested, for H incorporation, which included self-compensation by vacancy creation.

W.C.Hughes, M.L.Swanson, J.C.Austin: Journal of Electronic Materials, 1993, 22[8], 1011-6