RAMAN-SPECTROSCOPY OF GAAS-ALAS SUPERLATTICES - A STUDY OF INTERFACE ROUGHNESS

The roughness of the interfaces in a series of (AlAs)n1 (GaAs)n2 (AlAs )n3 (GaAS)n4 superlattices has been measured by comparing the Raman fr equencies of the confined GaAs-like LO phonons with results from a lin ear chain model modified to incorporate a description of the roughness . A new model is developed which shows that the interface roughness pa rameter W of a layer of average thickness n monolayers can be describe d by the expression W2 = alphann(s)/(alphan + n(s), with alpha = 1 and n(s) = 2 and 5 for GaAs and AlAs, respectively.