Electron mobility measurement inn−GaAsat low-temperature impurity breakdown

Abstract

Using a combination of the standard Hall technique and the photoluminescence imaging of galvanomagentic transport, free-electron density and mobility have been measured in the regime of filamentary current flow after the electric breakdown of n-GaAs at the temperature of liquid helium. The data show good agreement with those acquired by the geometrical magnetoresistance effect and by the optical Hall angle measurement. By comparing the mobilities obtained by independent techniques, arguments have been found indicating significant neutral impurity scattering in the post-breakdown regime. In the pre-breakdown regime variable range hopping has been concluded as the dominant transport mechanism.