Investigation of semiconductors with defects using Raman scattering
Landau Institute for Theoretical Physics, Russian Academy of Sciences, ul. Kosygina 2, Moscow, 119334, Russian Federation
The influence of defects and carriers on lattice dynamics, especially on Raman scattering from semiconductors and metals, is considered; a comparison of the theory with experimental data is made. Phonon scattering by point, line, and plane defects produces a phonon shift and phonon broadening, which influence the Raman line shape. This effect is used for investigating strain at interfaces and for characterizing semiconductor devices. Phonon interaction with carriers involves a Coulomb field excited by optical-phonon vibrations. Our treatment of the electron-phonon interaction is based on the Born-Oppenheimer adiabatic approximation. The effect of carriers is essential near the edge of the ω-k region where Landau damping appears due to the electron-hole excitation. A possibility to determine the electron-phonon coupling constant from experiments with the phonon-plasmon coupled modes is discussed.