Hot-electron luminescence: A comparison of GaAs and InP

A detailed study of the properties of hot-electron luminescence at T=2 K in lightly p-type GaAs and InP is presented. First, substantial changes are observed in the spectra as the angle between the incident laser electric field and the crystal axes are varied. The combination of the spherical nature of the acceptor wave function (i.e., the wave function of the hole bound at the acceptor) and the strong anisotropy of the heavy-hole valence band are shown to be the causes of the changes. Second, hot luminescence spectra in GaAs and InP are compared as a function of laser energy. The relative changes in the intensity of these spectra give a detailed picture of the k-space dependence of the acceptor wave function, and further provide a determination of intervalley scattering times in GaAs. This last measurement is compared with previous measurements and calculations of intervalley scattering times.