Semiconductor (II-VI) hetero-epitaxial layers were grown on (001) GaAs substrates, by means of metalorganic chemical vapor deposition, at a temperature of 365C. In the case of CdTe/ZnTe/GaAs, (Cd,Hg)Te was sometimes grown on top of the CdTe. The interfaces were examined by using transmission electron microscopy. It was found that the ZnTe/GaAs interface was abrupt and contained misfit dislocations. On the other hand, there was no transmission electron microscopic contrast at the ZnTe/CdTe interface. Threading dislocations were also observed. The (Cd,Hg)Te which was grown on top of CdTe contained a remarkably low dislocation density, and this was attributed to the interdiffusion multi-layer process which was used in their preparation. This involved firstly depositing alternate HgTe/CdTe layers (with a misfit of about 0.3%). This initially strained superlattice eliminated dislocations. When X-ray microanalysis and secondary ion mass spectrometry were used to detect the presence of impurities in the layers, As and Ga were found in concentrations of up to a few % in II-VI semiconductors. Their presence was attributed to interdiffusion in the lattice, and along dislocations.

G.Patriarche, R.Triboulet, Y.Marfaing, J.Castaing: Journal of Crystal Growth, 1993, 129[3-4], 375-84