Hole Transport in Arsenic-Doped Hg1−x Cd x Te with x ≥ 0.5

Abstract

Hole transport in arsenic-doped p-type Hg1-xCdxTe epitaxial layers with x ≥ 0.5 has been studied employing Hall-effect measurements and theoretical modeling of hole scattering mechanisms. The hole transport parameters extracted from four different Hg1-xCdxTe films with x = 0.50, 0.56–0.58, 0.65, and 0.80, were analyzed using an iterative solution of Boltzmann’s transport equation. Hole mobilities in the samples with x values of 0.5 and 0.56–0.58 were found to be predominantly limited by ionized impurity scattering, and exhibited relatively high impurity compensation ratios ≥2. The sample with x = 0.65 exhibited the highest hole mobility, a low compensation ratio of 1.05, and mobility characteristics were limited predominantly by polar optical phonon scattering at temperatures ≥200 K. Hole mobility in the sample with x = 0.80 was found to be limited by polar optical phonon scattering and ionized impurity scattering (compensation ratio 1.20–1.56). Although the sample temperatures employed were not sufficiently low to unambiguously discriminate the scattering strength of static strain and dislocations, the experimental hole mobility characteristics cannot be adequately modeled if these two mechanisms are neglected. The ionization energy of the arsenic acceptor impurities was found to exhibit a quadratic dependence on the CdTe mole fraction.