Ensemble Monte Carlo study of electron transport in wurtzite InN

Abstract

Electronic transport in wurtzite phase InN is studied using an ensemble Monte Carlo method. The model includes the full details of the first five conduction bands derived from the pseudopotential method and a numerically calculated impact ionization transition rate using a wave-vector- dependent dielectric function. Calculated results for electron transport at both low and high electric field are presented and compared with available results from simpler methods. The dependence of the relevant transport properties on the parameters is discussed, in particular in regards to the uncertainties in the band structure and coupling constants. It is found that at a field of 65 kV/cm that the peak electron drift velocity is 4.2×107 cm/s. The peak velocity in InN is substantially higher than in GaN. The velocity field curve presents a noticeable anisotropy with respect to field direction. The peak velocity decreases to 3.4×107 cm/s for a field of 70 kV/cm in the direction perpendicular to the basal plane. The electron velocity at the onset of impact ionization reaches a value slightly lower than 2.0×107 and 1.0×107 cm/s for fields applied in the direction parallel and perpendicular to the basal plane. The low field mobility has been determined to be in the range of 3000 cm2/V s. The determination of the ionization coefficients is somewhat uncertain due to the lack of knowledge of the high energy phonon scattering rates. Nevertheless, the calculations presented here of the ionization coefficients and quantum yield provide a reasonably accurate estimate of the ionization process.