Study of the segregation process in GaAs/AlAs superlattices using Raman spectroscopy

A Raman scattering study of cation segregation in GaAs/AlAs ultrathin-layer superlattices grown with different temperatures and As pressures is report ed. The optical confined modes of the samples were measured. The kinetic se gregation model was modified in order to allow the calculation of the compo sitional profiles of the samples. After utilizing the Raman wavenumbers as references to adjust the calculated values by the next-nearest-neighbor lin ear chain model, it was possible to determine the parameters characterizing the segregation. It is shown that an increase in the pressure of As result s in a more abrupt compositional profile, equivalent to the decrease in the growth temperature. Copyright (C) 2001 John Wiley & Sons, Ltd.