Electric Field Effects on Hot Electron Luminescence from p-GaAs

Abstract

Photoelectrons in the conduction band of GaAs have energy, momentum and spin distributions determined by the anisotropic valence band structure and the optical matrix elements. In p-type GaAs, a small fraction recombine with acceptor states, producing a Hot Electron Luminescence (HEL) spectrum with a series of peaks due to discrete energy losses through LO-phonon emission. The highest peak has an energy structure due to warping of the initial heavy hole (HH) band. We report measurements of its lineshape and polarisation, identifying emission from electrons along particular k-directions. An electric field of 1 kV cm—1 distorts the momentum distribution, and this is reflected in the polarisation profiles. The lineshapes and profiles are modelled using a k · p band structure and optical matrix elements, the effect of the field being included using a k-broadening model.