Temperature characteristic of carrier scattering and dark resistivity of semi-insulating GaAs

Abstract

The electron mobility and the dark resistivity of undoped semi-insulating GaAs have been calculated theoretically over the temperature range from 5 to 500 K by taking into consideration all indispensable scattering processes, screening effects, and impurities compensation action. The two temperature characteristic curves of electron mobility and dark resistivity both exhibit unimodality. The peak value of the mobility as high as 11.4 × 105 cm2 V−1 s−1 can be achieved at 27 K, which is more than two orders of magnitude greater than that at 300 K. We analyzed the carrier relaxation rate due to scattering by ionized impurities, acoustic deformation potential, piezoelectric, and polar optical phonons. It is found that the unusually thermal characteristic is dominated by ionized impurity scattering, piezoelectric scattering, and polar optical phonon scattering in different temperature ranges, respectively. According to the scattering theory models, the dominant position relationships between the two different carrier scatterings induced by acoustical phonons in two-dimensional GaAs layer and bulk semi-insulating GaAs are discussed, respectively. The peak value of dark resistivity is about 1.29 × 1012 Ω cm at 154 K, which is more than five orders of magnitude greater than that at 300 K. The theoretical results are in good agreement with previously published results. Moreover, the dependence of the peak value of dark resistivity on the deep and shallow donor concentrations are obtained, respectively, and the mechanisms of the dependence are discussed. Understanding of thermal properties of dark resistivity and mobility can be used to optimize GaAs-based electronic and photonic devices’ performance in different temperature regimes.