Mixed optical phonon modes in semiconductor nanocrystals synthesized in porous amorphous Al2O3 matrix

Abstract

This work is devoted to experimental and theoretical studies of optical phonons confined in CdS nanocrystals grown inside a porous alumina matrix. The complete sets of phonon modes, confined in a spherical quantum dot and in a cylindrical quantum wire, are considered in the framework of a continuum model, which allows the mixing of all the expected types of vibrations. It is shown that the calculated phonon-related response in the far-infrared spectral region agrees qualitatively with the measured spectra of typical samples, providing an explanation for a rather unusual structure of the reflection and transmission spectra.