Electron transport in direct-gap III-V ternary alloys

Abstract

Electron drift, Hall mobility and thermoelectric power in InP_xAs_1-x, Ga_xIn_1-xAs and InAs_xSb_1-x have been calculated by an iterative solution of the Boltzmann equation. A Kane-type band structure corrected for the lattice disorder is assumed. All the relevant scattering mechanisms are included together with band non-parabolicity, wavefunction admixture, degeneracy of the distribution function and screening of the scattering probabilities due to free carriers. Only the ionised impurity concentration (N_i) and the alloy scattering potential ( Delta E_a) have been treated as adjustable parameters to be determined from a fit with the experimental data. Variations of the other different material parameters across the alloy system have been taken from different sources, or reasonable assumptions are made regarding such variations. A large number of experimental results on both mobility and thermoelectric power are considered and good agreement is obtained with Delta E_a larger than that given by the difference in electron affinity between the constituent compounds.