Resonant Light Scattering by Optical Phonons in a Homoepitxial n-GaP Nanolayer Grown on a (001)n-GaP Substrate

Abstract

The results of detection of resonant amplification of light scattering intensity by optical phonons in a homoepitaxial nanoscale 70 nm thick n-GaP layer grown by gas-phase epitaxy from organometallic compounds on a conducting strongly doped n-GaP crystal substrate oriented along the (001) axis have been presented. It has been shown that it is possible to detect rather narrow bands of second-order light scattering lines in the frequency range from 600 to 800 cm–1 at room temperature in the Raman light scattering spectrum of such a (001) n-GaP nanolayer in the n-GaP/n-GaP (001) sample in comparison with those in the spectrum of a high-resistance (001) si-GaP crystal sample. It has been established that such bands are caused by the total combinations and overtones of transverse TO(Γ) and longitudinal LO(Γ) optical phonons with wave vectors corresponding to the points Σ, K, X, L, and Γ of the Brillouin zone of a GaP crystal. It has been shown that the light scattering is resonant and caused by the presence of impurities because of the exciton-phonon interaction.