Epitaxial narrow-gap PbSe was grown onto Si(111) substrates by means of molecular beam epitaxy, with a BaF2/CaF2 buffer layer. The tensile strain which built up during cooling after growth, due to thermal expansion mismatch, was relaxed by the creation and movement of misfit dislocations in the main glide system. The thermal mismatch strain relaxed even at liquid-N temperatures, and after much thermal cycling between room temperature and 77K. Even after more than 1000 such cycles, no substantial numbers of new threading dislocations formed, according to the observed widths (about 150s of arc for 3-thick layers) of the X-ray rocking curves. Some strain hardening was observed. Plastic relaxation occurred at each cycle, and the cumulative plastic deformation after 1400 thermal cycles could be as high as 400%. The strain was relaxed mainly by the threading ends of misfit dislocations, which moved back and forth during each cycle in spite of the presence of a considerable density (about 108/cm2) of grown-in sessile dislocations.

H.Zogg, S.Teodoropol: Journal of Crystal Growth, 1995, 150[1-4], 1186-9