Optical phonon modes and electron-phonon interaction in a quantized CdS spherical film

The confined longitudinal-optical (LO) phonon and surface-optical (SO) phonon modes of a quantized US spherical film are discussed within the dielectric continuum (DC) approximation. Two branches of SO phonon modes localized at the inner and outer surface of the film have been investigated. The frequencies of the SO phonons are found to be dispersed and radius dependent for small size systems. When the quantum number l --> infinity, the frequencies of each SO modes converge to the frequency values of the single planar heterostructure. The coupling intension between electron and SO phonons is found to be size-dependent and the electron-SO phonon interaction with different well-width has also been discussed. (C) 2008 Elsevier B.V. All rights reserved.