A phonon-plasmon coupling study on Ge-doped GaAs epitaxial films

The phonon-plasmon coupling of p-type, Ge-doped gallium arsenide films have been study using Raman spectroscopy. The films were grown epitaxially on (100) GaAs substrates by liquid phase epitaxy employing Ge as dopant at various concentrations, which resulted in films with hole densities in the range of 5x1017-5x1020 cm-3. The Raman experiments were performed at near backscattering geometry at room temperature, 100 and 20 K. In the configuration employed only the LO mode is allowed. The intensity, frequency and linewidth of this mode have been discussed in terms of LO phonon-plasmon coupling due to impurity-induced Froehlich interaction and or deformation potential mechanisms. copyright 1996 American Institute of Physics