The spatial origin of exciton and defect photoluminescence lines at 77K was studied. Scanning electron microscopy was used to obtain cathodoluminescence images, which were spectrally resolved with the aid of optical filters. It was observed that the exciton and defect luminescence lines originated from different spatial locations in the sample. The exciton line appeared to originate from 2 different locations; one of which was clustered dislocations. The results undermined the validity of the generally accepted criterion that a large ratio of exciton to defect emission in the luminescence spectrum of CdTe at 77K implied good crystal quality.

L.O.Bubulac, J.Bajaj, W.E.Tennant, P.R.Newman, D.S.Lo: Journal of Crystal Growth, 1988, 86[1-4], 536-43