LINEAR-CHAIN-MODEL INTERPRETATION OF RAMAN-SCATTERING FROM ZNSE/ZNTE SUPERLATTICES AND ZNSEXTE1-X MIXED-CRYSTALS

We study the vibrational dynamics of strained-layer superlattices of ZnSe/ZnTe, using Raman spectroscopy together with calculations in a linear-chain model. Our analysis suggests (1) that the superlattices are free standing, i.e., separated elastically from their substrates, whether grown on GaAs or InP, and (2) that the degree of strain within the superlattice layers depends strongly on the superlattice period LAMBDA. From essentially none at LAMBDA = 30 angstrom, the relaxation of the strain increases with LAMBDA until full relaxation is encountered at LAMBDA = 90 angstrom. Additionally we discuss briefly the evidence for interfacial disorder in the superlattices and the single-mode spectra of ZnSexTe1-x mixed-crystal alloys.