Subband electron mobility in selectively delta -doped gaAs/GaAlAs heterostructures with high carrier density

摘要

We synthesised and investigated new high-carrier-density GaAs/GaAlAs heterostructures with combined doping, that is with delta-doping by SI of GaAs and uniform doping by Si of GaAlAs layers. The Hall effect and magnetoresistance were investigated for the structures with distances L delta between heterojunction and delta-alyer from 200A to 1200A. The enhanced 2D electron concentration achieved was 1.1~*10~(-13) cm~(-2) in six filled subbands for the sample with L delta chemical bounds A. Electron mobilities and concentrations in each 2D subband have been extracted from the magnetoresistance and Hall effect data. The electron mobility due to the scattering from ionized impurities has been calculated in the case when several subband are occupied.