Misfit dislocation behaviour in epitaxially grown PbTe xSe 1 − x/PbTe heterojunctions

Abstract

In PbTe x Se 1 − x /PbTe heterojunctions the density of misfit dislocations increases as the mole fraction of selenium increases. If the misfit is small the misfit dislocations are segmented, while for a large misfit they form an interwoven network. The former are mobile during an annealing process and the latter are quite stable since they cannot climb independently. The density of the misfit dislocations for films with a small misfit agrees quite well with that predicted theoretically, in contrast with that for junctions with a large misfit where the density of misfit dislocations is lower than that expected from theory. Therefore, a large part of the misfit is relieved by the residual strain. This should be attributed to the difficulty of generation of the misfit dislocations, which are formed mainly as half-loops.