Layers of Te-doped material were grown by means of liquid-phase or vapor-phase epitaxy, and were studied using deep-level transient spectroscopy, photoluminescence, and thermally stimulated capacitance techniques. In addition to the well-known Te-DX center, the deep-level transient spectra revealed 2 distinct peaks. These 2 traps, of unknown origin but which exhibited DX-like characteristics, were donor-related DX centers that were generated by residual Si and S contamination. This result, together with data on Si- and S-implanted samples, solved a long-standing problem concerning the origin of these traps and their relationship to local environmental effects. Apparently for the first time, characteristic thermal and optical barriers were established for Si-related DX centers in this material. It was noted that there was a danger of misinterpretation of data in cases where residual contamination was present. This was particularly true of the present material.

E.Calleja, F.J.Sanchez, E.Muñoz, E.Vigil, E.Omnès, P.Gibart, J.M.Martin, G.G.Díez: Physical Review B, 1996, 53[12], 7736-41