Brillouin scattering study of surface acoustic waves in indium-implanted GaAs

Using high-contrast Brillouin spectroscopy we have investigated surface acoustic waves in supported layers formed on GaAs substrates by 250 keV In+ implantation and subsequent rapid thermal annealing. The angular dispersion of surface acoustic wave velocity in the implanted and annealed layers shows elastic anisotropy characteristic for the (001) planes of the substrate. The values of both Rayleigh and pseudosurface acoustic wave velocities are in reasonable agreement with, but nevertheless consistently lower than, those calculated using the elastic constants of InxGa1-xAs, where the In composition x = 0.2 has been obtained from the Rutherford backscattering measurements. (C) 2000 Elsevier Science Ltd. All rights reserved.