Electron effective mass and mobility in heavily doped n-GaAsN probed by Raman scattering

We investigate inelastic light scattering by longitudinal optic phonon-plasmon coupled modes (LOPCMs) in a series of heavily Se-doped, n-type GaAs1-xNx epilayers with x < 0.4%. We perform a line shape analysis of the LOPCM spectra to estimate the optical effective mass, m(opt)*, and the scattering time of the conduction electrons in GaAsN. We use these results to evaluate an effective carrier mobility for our samples. The values thus obtained, which we compare with measured electron Hall mobilities, indicate that the x-dependence of the mobility in GaAs1-xNx is dominated by the scattering time, rather than by the variation of the electron effective mass. The Raman analysis yields m(opt)(*) values that are lower than those obtained from the band anticrossing model. (C) 2008 American Institute of Physics.