A luminescence at 1.491eV was detected, at liquid He temperatures, which arose from epilayers that were heavily doped with 1. The relatively sharp emission band (0.0044eV full width at half-maximum) was observed under both above-bandgap and below-bandgap excitation. The intensity of the 1.491eV emission depended markedly upon the sample temperature, and could be detected only below 45K. By using the tunable output of a Ti-doped sapphire laser, selective excitation of the emission was used to identify the recombination center. A localized mode of 0.0365eV was found which was much larger than the 0.0213eV bulk CdTe mode, and was associated with the defect center. This defect was identified as being a donor-acceptor pair complex which resulted from nearest-neighbour cation (NaCd) and anion (ITe) point defects. The energy level which was associated with the (NaCd--ITe+) neutral pair was about 0.115eV below the CdTe conduction band.

J.Lee, N.C.Giles, C.J.Summers: Journal of Applied Physics, 1995, 77[9], 4544-7