By using spark-source mass spectrometry, atomic absorption spectrometry, and various optical techniques, a study was made of the concentrations and axial distributions of point defects and precipitates in Bridgman crystals which had been grown with or without extra Cd. It was found that the concentrations of substitutional impurities were controlled by Cd and Te vacancies which formed during growth. When the crystals were cooled after growth, some of the Cd vacancies were occupied by impurity atoms, while others clustered so as to form Te precipitates. The vacancy concentrations were modified, and the latter reaction was suppressed, during growth under a Cd over-pressure. Intentional doping with halogens led to the formation of persistent Te-site donor/Cd-vacancy complexes.

H.Zimmermann, R.Boyn, C.Albers, K.W.Benz, D.Sinerius, C.Eiche, B.K.Meyer, D.M.Hoffmann: Journal of Crystal Growth, 1993, 128[1-4], 593-8