Interfacial and Confined Optical Phonons in Wurtzite Nanocrystals

摘要

We derive within the dielectric-continuum model an integral equation thatdefines interface and confined polar optical-phonon modes in nanocrystals withwurtzite crystal structure. It is demonstrated theoretically, that while thefrequency of confined polar optical phonons in zincblende nanocrystals is equalto that of the bulk crystal phonons, the confined polar optical phonons inwurtzite nanocrystals have a discrete spectrum of frequencies different fromthose of the bulk crystal. The calculated frequencies of confined polar opticalphonons in wurtzite ZnO nanocrystals are found to be in an excellent agreementwith the experimental resonant Raman scattering spectra of spherical ZnOquantum dots.