Changes in the cathodoluminescence spectra of thin ZnS films, which had been grown by means of molecular beam epitaxy onto GaAs(001), were studied by using a low-temperature cathodoluminescence measurement system combined with transmission electron microscopy. It was found that structural defects such as dislocations and stacking faults formed in the ZnS films and seriously affected the cathodoluminescence intensity within a distance of 200nm from the interface. Their effect became negligibly small at distances of more than 600nm. The relative intensities of the exciton-associated emissions were small in comparison with non exciton-associated emissions for thin samples that had relatively large stacking-fault densities. This suggested that the stacking faults which accompanied the partial dislocations suppressed the generation of excitons. The peak of the non exciton-associated emission shifted markedly to longer wavelengths as the epitaxial layer thickness became less than 200nm. This peak shift was attributed to internal stress changes in the ZnS film; due to the stress which was caused by the lattice mismatch, and relaxation due to the introduced defects.

Influences of Interfacial Misfit Dislocations on Cathodoluminescence of ZnS/GaAs(001) Studied by Transmission Electron Microscopy T.Mitsui, N.Yamamoto: Japanese Journal of Applied Physics - 1, 2000, 39[3A], 1172-5