RAMAN-SCATTERING STUDY OF PHOTOEXCITED PLASMA IN SEMICONDUCTING AND SEMIINSULATING INP

Raman scattering is used to study the photoexcited electron-hole plasm a generated under continuous-wave laser excitation in semiconducting a nd semi-insulating InP at room temperature and at 80 K. Coupled plasmo n-LO-phonon modes are detected in both types of samples, even at low l aser excitation power. The coupled modes are clearly resolved from the depletion-zone LO mode in high-resolution measurements. This makes po ssible the accurate determination of the frequency and width of the un screened LO-phonon peak. The photoexcited-plasma density is obtained f or different incident laser powers by fitting the Raman spectra with a line-shape calculation based on a Lindhard-Mermin dielectric function that takes into account electron and hole contributions. [S0163-1829( 98)12719-4].