Dependence of residual strain on size in small epitaxial islands

Abstract

Vincent's measurements of the average strain in small Sn islands grown epitaxially on SnTe between 140°C and 200°C showed a saw-tooth dependence on island width. He explained this behaviour by assuming that a given interfacial mismatch cannot be entirely compensated by an integral number of dislocations, and that the residual part must be accommodated by elastic strain. The present considerations show how a saw-tooth dependence can be calculated on the basis of lowest energy using a model in which the interaction at the interface of the overgrowth and substrate is represented by a periodic potential. The resutls of the calculations support the approximations suggested by Vincent and others.