Raman spectroscopy of II–VI semiconductor nanostructures: CdS quantum dots

Information about confinement effects and dot–matrix interactions of CdS nanoparticles was obtained from resonance Raman spectroscopy. The quantum dots had diameters of 3 and 5 nm and were prepared with and without organic spacer groups. It was found that the spacer improves the quality of the nanocrystallites. No phonon confinement shift could be observed even for the small quantum dots. The linewidths of the overtone series point to a mechanism of vibrational relaxation which is dominated by the decay of the LO phonons into acoustic phonons. Copyright © 2003 John Wiley & Sons, Ltd.