Effects of optically excited carriers on Raman spectra from InP

Abstract

Raman spectra from InP were measured at various power densities of the exciting laser. Concentration of the optically excited excess carriers Δn calculated from the frequency of the coupled longitudinal optical phonon‐plasmon mode was about 0.5–1.7×10¹⁷ cm⁻³ at the laser power density of 5×10² W/cm² for InP with equilibrium carrier concentration 0.9–5×10¹⁷ cm⁻³. Surface recombination velocity estimated from Δn assuming that the bulk lifetime was larger than 10⁻⁷ s was 1–8×10³ cm/s. Such dependence of Raman spectra on laser power density could not be observed for GaAs.