Temperature dependence of electron mobilities in InN

InN allows the possibility of engineering nitride materials with bandgaps as small as 0.7 eV. We have calculated electron mobilities in InN taking into account the non-parabolicity of the conduction band, as well as the standard scattering mechanisms of acoustic and optical phonons and Coulomb scattering from charged impurities. Although our calculations explain well the experimentally measured mobilities at temperatures higher than about 200 K, the measured mobilities in lightly doped InN at low temperatures decrease in a way that cannot be accounted for by the standard theory. We discuss the characteristics and possible origins of the additional mechanism that must be included in the calculations in order to fit the experimental results.