PHOTOLUMINESCENCE OF ZNSE/CDSE SHORT-PERIOD SUPERLATTICES GROWN BY SELF-LIMITING MONOLAYER EPITAXY

A series of symmetric ZnSen/CdSen superlattices (n=2-6, where n is the number of monolayers) was prepared by a novel growth method, the self-limiting monolayer epitaxy. For n less-than-or-equal-to 3, the low temperature photoluminescence spectra of these superlattices are dominated by near-band-gap emission with full widths at half maximum (FWHM) of 17 meV. For longer periods the photoluminescence intensity drops drastically and the FWHM increases by a factor of 2 which is attributed to the formation of misfit dislocations. The energetic positions of the photoluminescence peaks are in good agreement with transition energy calculations based on a Kronig-Penney-type model.