The self-diffusion of Ge was studied by monitoring the Raman scattering of optical phonons from isotopic (70Ge)n(74Ge)m superlattices. Raman spectra for a series of superlattices, where n and m were equal to 8, 12, 16 or 24 monolayers, were obtained after annealing at 500C for various times. The results were compared with theoretical calculations that were based upon a planar force constant model and bond polarizability approach. The average value of the mass of an atom in each atomic plane was given by the diffusion profile, after solving Fick’s diffusion equation for the superlattice. The estimated value for the self-diffusivity at 500C was 5.50 x 10-24m2/s. This value agreed closely with previous data.

E.Silveira, W.Dondl, G.Abstreiter, E.E.Haller: Physical Review B, 1997, 56[4], 2062-9