A combined Raman and ab initio lattice dynamical study of ultrathin (GaAs)4(AlAs)4 superlattices, focusing mainly on AlAs-like vibrations, clearly shows that a significant amount of interdiffusion occurs in these samples when grown at conventional molecular-beam epitaxy temperatures between 580 and 640-degrees-C. At these temperatures, growth interruption is found to have little impact on the structural quality of the superlattices.
