Optical study of interactions of hydrogen with dislocations in CdTe

The effect of hydrogenation on defects associated with dislocations has been studied in n-type CdTe crystals with the help of cathodoluminescence imaging and photoluminescence spectra. Dislocations were introduced by performing indentations on the Cd(1 1 1) and Teð% % 1 % 1Þ crystal faces using a Vickers microhardness apparatus. Hydrogenation was achieved by annealing the samples in closed ampoules at 500 � C for 70 h under deuterium atmosphere at a pressure of 700 mbar. Cathodoluminescence images of hydrogenated samples show a removal of the long arms of the indentation rosette on Te face and short arms on Cd face. This is accounted for in terms of the formation of TeH2-like volatile entities as Te atoms are involved in both cases. Photoluminescence spectra indicate that the general effect of plastic deformation is to create acceptor centres related to mobile impurities (Cu) and to Cd vacancies. Those acceptors may be passivated by formation of neutral complexes with deuterium.