Dislocations in Hg1−xCdxTe/Cd1−zZnzTe epilayers grown by liquid-phase epitaxy

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Abstract
Misfit and threading dislocations in HgCdTe epitaxial layers grown on (111)B CdTe and CdZnTe substrates by liquid‐phase epitaxy have been investigated quantitatively by the etch pitting technique. In the HgCdTe/CdTe heterojunction, it has been found that the misfit dislocations introduced at the initial stage of epitaxial growth move to the 〈111〉 direction and distribute in such a way that they completely accommodate the mismatching strain of the compositional gradient caused by the Hg‐Cd interdiffusion. On the other hand, in HgCdTe/CdZnTe heterojunctions, misfit dislocations were found to be pinned by Zn out‐diffused from the substrate. For a proper ZnTe mole fraction in the CdZnTe substrate, the linear dislocation‐pit density on the (1̄10) cleaved and etched surface was confirmed to decrease to about 1% of that using a CdTe substrate. It has also been found that the density of dislocations threading into the epitaxial layer was determined not by the magnitude of lattice mismatch, but by the dislocation density of the substrate.