Theoretical study of hole transport in ZnSe

Abstract

Hole mobilities in ZnSe were calculated by solving the Boltzmann transport equation by the variational method, with all major scattering mechanisms included. Valence-band state symmetries were accounted for, both intra- and interband scattering terms for light and heavy holes were included, and generalized Fermi–Dirac statistics were used throughout. Screening of polar optical phonon and ionized impurity scatterings was also included. The contributions of all component scattering mechanisms to the total hole mobility as a function of hole concentration at 300 and 77 K, have been calculated for the first time. The influence of the compensation ratio, and the concentration of ionized impurities on both the hole mobility and resistivity has also been calculated for the first time; these results are shown to facilitate rapid and direct evaluation of electronic materials quality. In addition, the theoretical model was used to calculate the temperature dependence of the hole mobility in ZnSe, which proved to be in excellent agreement with available experimental data, confirming the choice of scattering parameters. Ultimate limits for the hole mobility in ZnSe at 300 and 77 K were calculated to be about 110 and 2000 cm2/V s, respectively, given zero compensation. Finally a derivation of the heavy-hole effective mass in ZnSe is presented, which yields a value 0.60 m0.