Electron damage in In2Te3 — A defect tetrahedral semiconductor

Indium sesquitelluride (In2Te3) is typical of a large class of defect semiconductors which are tetrahedrally bonded but which possess room temperature vacancy concentrations of the order of 5.5 &time; 10 cm⁻³. It has been proposed by V.M. Koshkin et al. that these semiconductors can not preserve non-equilibrium point defect concentrations. This hypothesis has been tested in the present experiments by electron irradiating In2Te3 at 77 K with 1 MeV electrons and using electron paramagnetic resonance (EPR) to observe the results. Several different resonances have been observed with g values ranging from 1.979 to 2.133 and possessing X-band line widths of 7 to 42 gauss. All of the resonances except the largest one at g = 2.019 have orientation dependent g values and all anneal at different temperatures suggesting that several different defect centers have been produced. Because the 1 MeV electron defect production rate for these centers at 77 K (0.01 to 0.1 defects/electron) is typical of defect production rates observed in other compound semiconductors, the hypothesis proposed by Koshkin et al. is incorrect. The stability of these defects is somewhat lower than in non-defect semiconducting compounds, however, since none of these defects survive prolonged room temperature annealing and since no additional complex centers formed by thermal annealing have been detected.