We have used a two-band model (heavy and light holes) to calculate the transport properties ofp-type GaAs. The scattering mechanisms included are acoustic-mode deformation potential, acoustic-mode piezoelectric potential, polar- and nonpolar-mode deformation potential, ionized impurity, and space charge. Interband scattering is included explicitly for the optical phonons and phenomenologically for the acoustic phonons. The intraband polar optical-mode scattering, for which a relaxation time cannot be defined, was calculated by using the numerical method of Fletcher and Butcher. The acoustic deformation-potential parameter and the coupling coefficient for interband scattering were calculated by fitting the theory to Hall-mobility data for both pure and doped samples. We have determined ionized-impurity and space-charge contributions for two of our samples, one doped with Cr and exhibiting an 0.33-eV activation energy (Cr4+/Cr3+), and the other heat-treated and exhibiting an 0.14-eV activation energy. The transport fit was carried out self-consistently with a statistical fit of the p vs T data, to determine the relevant donor and acceptor concentrations. Individual plots of the mobility contributions from the various scattering mechanisms are also presented. Finally, useful plots of the Hall mobility and Hall r factor, as functions of carrier density and compensation ratio, are provided to aid others in the analysis of their samples. An important conclusion of this study is that the light-hole band strongly influences the transport properties, even though its density of states is small compared to that of the heavy-hole band.
Lee, H. J.,
& Look, D. C.
(1983). Hole Transport in Pure and Doped GaAs. Journal of Applied Physics, 54 (8), 4446-4452.