Resonant tunneling spectroscopy of hot minority electrons injected in gallium arsenide quantum wells

Abstract

We have employed a new electron spectroscopy technique based on resonant tunneling to study hot minority-electron transport in GaAs quantum wells, following ballistic injection. Direct information on the momentum and energy distribution perpendicular to the heterointerfaces is obtained from the measured resonant tunneling current without requiring derivative techniques. For injection energies of ≂0.2 eV, strong energy and momentum relaxation occurs over distances≲250 Å making impossible the observation of minority-electron ballistic transport in heavily doped (>1018 cm−3) GaAs. The energy distribution is found to be strongly non-Maxwellian; from our data we can infer electron scattering times ≤10−14 which are consistent with recent evidence of strong electron-hole scattering in GaAs quantum wells.