The effect of carrier densities and compensation ratios on the electron mobility of InAs xP 1−x

Abstract

The electron mobility of InAs x P 1− x has been calculated for an ionized impurity concentration between 10 14 cm −3 and 2 × 10 17 cm −3 at 300 K and 77 K by using Matthiesson rule formalism and the variational method. These results are shown to be in reasonably good agreement with experimental mobilities. The electron mobilities of InAs 0.13P 0.87, InAs 0.5P 0.5 and InAs 0.80P 0.20 with temperature are also calculated for a range of ionized impurity concentration. Since the compensation ratio of acceptor and donor doped impurities, the inhomogeneity of the samples and other effects are not taken into account, these results represent the upper theoretical limit of electron mobility in InAs x P 1− x . The dependence of electron mobility of InAs x P 1− x on carrier concentration and compensation ratio are also studied for these alloys. The compensation ratio does not have a significant effect on mobility at room temperature, particularly for low carrier density where ionized impurities are relatively unimportant, while at 77 K, the effect of compensation is very significant. The upper theoretical electron mobilities for x = 0.13, 0.5 and 0.8 are 4500, 6500 and 13,000 cm 2 V −1 s −1 at 300K and 50,000, 50,000 and 150,000 cm 2 V −1 s −1 at 77 K, respectively. The various accepted methods used in the calculation of electron mobility are briefly discussed.