Band Folding and Mixing in Ultrathin GaAs-AlAs Superlattices

The oscillator strength of optical transitions involving folded states is crucial for the possible applications of semiconductor superlattices. This is of particular importance in cases where the layering of two indirect-gap semiconductors results in a direct-gap superlattice. The use of these articial structures as optical devices requires large oscillator strengths associated with the new direct gap.