The long-term evolution of the 77K conductivity of n-type Hg0.79Cd0.21Te samples, which had been prepared by reactive ion-etching in H and Ar plasmas, was studied. It was shown that, after storage at room temperature, the conductivity decreased to less than half of its initial value within 2 x 105s. The relaxation time was about 1000 times longer than the etching time. An increase in the storage temperature, to 323K, resulted in a 5-times faster rate. The results were interpreted as being a result of the release and out-diffusion of donor-like Hg interstitials which were captured on defects within the sample during reactive ion-etching. Numerical solution of the diffusion equation permitted the estimation of the diffusion constant of Hgi at room temperature. This diffusivity was greater than 10-8cm2/s. Traps with concentrations of 1016 and 1015/cm3, with formation energies of –0.5 and –0.6eV, respectively, were detected. The traps were attributed to complexes which were formed from extrinsic acceptors and bound Hg interstitials.

Dynamics of Native Point Defects in H2 and Ar Plasma-Etched Narrow Gap (HgCd)Te. E.Belas, R.Grill, J.Franc, P.Moravec, R.Varghová, P.Höschl, H.Sitter, A.L.Toth: Journal of Crystal Growth, 2001, 224[1-2], 52-8