The structure of CdTe/CdZnTe strained-layer superlattices which blocked threading dislocations was studied. Since residual strain in hetero-epitaxial CdTe offset the strain which was introduced by strained-layer superlattices such lattices, when located near to the CdTe/GaAs interface, were suggested to be constructed with a large misfit force in place. The surface dislocation density of CdTe was found to be reduced by a factor of 2.5 by using 2 strained-layer superlattices, and by a factor of 4.3 in the case of 4 strained-layer superlattices. The etch-pit density of a HgCdTe layer which was grown onto this strained-layer superlattice buffer layer was reduced. This was a beneficial side-effect of a reduction of dislocations in the buffer layer. Thus, strained-layer superlattices effectively blocked dislocations when properly designed. The dislocation density could be further reduced by increasing the number of strained-layer superlattices.

I.Sugiyama, A.Hobbs, T.Saito, O.Ueda, K.Shinohara, H.Takigawa: Journal of Crystal Growth, 1992, 117, 161-5