Surface phonons modes: a tool to determine the quantum dot morphologyAbstract
We report here theoretical and experimental studies on the spatial confinement of phonons in ternary CdSxSe1-x nanocrystals embedded in a glass matrix formed by the composites SiO2-Na2CO3-B2O3-Al2O3 doped with CdO, S and Se. We determined the morphologic characteristics of the nanocrystals by analyzing the dependence of surface phonon modes on the geometrical parameters. The calculated frequencies are compared with values from Raman spectra of CdSxSe1-x nanocrystals grown under different thermal treatments. A good correlation between experimental and calculated CdS-like and CdSe-like surface optical modes is observed. Raman selection rules and their connection with the nature of the surface optical phonons is discussed.
Quantum dots; Raman scattering
