Dominant mechanisms of electron scattering in ultra-dilute GaAsN

The dominant electron scattering mechanisms in GaAsN were investigated by analysing the Hall electron mobility and photoluminescence (PL) spectrum. The GaAsN thin films were grown by chemical beam epitaxy. The temperature dependence of the electron mobility indicated that polar optical phonon (POP) scattering was dominant in GaAs and GaAs: N-0.0003 near room temperature. By increasing nitrogen compositions up to around 0.1%, the temperature dependence of the electron mobility became from T-1.23 to T-0.5. It indicated that the dominant scattering changed from POP to alloy scattering with nitrogen composition. The full width at half maximum of the PL spectra suggested that the large potential fluctuation at conduction band edge did not exist in GaAsN grown by chemical beam epitaxy. The theoretical electron mobility of POP and alloy scattering with large effective mass which was obtained by Masia et al., Dennecker et al., and Ibanez et al. agreed with the determined electron mobility. Therefore, the POP and alloy scattering with the large effective mass were considered to be the origin of the low electron mobility of GaAsN. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim