ESTIMATION OF STRAINS IN MBE-GROWN ZNSE FILMS BY RAMAN-SCATTERING

LO phonon frequency of ZnSe thin films on GaAs grown by molecular beam epitaxy (MBE) is measured from 20 to 300 K by Raman scattering. The frequency shift of the ZnSe LO phonon is estimated in terms of elastic strain due to lattice mismatch and thermal strains due to the difference in thermal expansion coefficients of film and substrate. Strains due to lattice mismatch for thin films are dominant at high temperatures, while thermal strains due to large difference between growth and measurement temperatures are dominant at low temperatures. The temperature dependence of full width of half maximum (FWHM) in the LO phonon spectra of ZnSe is discussed in terms of imperfection and phonon contribution. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA