Spin-flip and acoustic-phonon Raman scattering in CdS nanocrystals

Abstract

We report on spin-flip Raman scattering and on Raman scattering by acoustic phonons in CdS nanocrystals embedded in a glass matrix. We discuss both the spin-flip and the acoustic-phonon Raman spectra on the basis of the interaction of size-quantized electronic excitations with nonconfined acoustic vibrations. The polarization of spin-flip Raman scattering in the Faraday and Voigt configurations is analyzed in comparison with that for bulk CdS. The effective electron g factor has been measured as a function of the quantum dot size.

Confinement‐, surface‐ and disorder‐related effects in the resonant Raman spectra of nanometric CdS1−xSex crystals

“…Special attention is paid to resonant Raman scattering by acoustic phonons, enabling estimations of nanocrystal size [2,3,15,21]. The changes observed in the first-order Raman spectra of glass-embedded nanometerscale CdS 1-x Se x crystals with respect to the bulk material are analyzed in view of relaxation of confinement-related selection rules [14,16,[20][21][22][23], surface phonon modes [14,16,24,25], and compressive strain due to the glass matrix pressure [26][27][28]. A special study is devoted to the effect of disorder on the Raman spectra of CdS nanocrystals [29].…”

Effect of the surface on the electron quantum size levels and electrongfactor in spherical semiconductor nanocrystals

“…The variation of g s with energy can be connected with the energy dependence of the bulk electron gfactor. 11 The eight band Kane model, that is used to describe the electron energy spectra in most direct gap semiconductors, gives the following dependence of the electron g-factor g c (E) on its energy, E: 22,23 …”

Raman-Brillouin light scattering in low-dimensional systems: Photoelastic model versus quantum model

“…6,7 The RBQM has been used to extract characteristic features of the electronic states such as localization and correlation lengths. 21 These basic ideas have been recently extended to semiconductor quantum dots to include three-dimensional confinement effects 22,23 and spatial ordering effects. [24][25][26][27][28][29][30] Despite the fact that the PEM and RBQM were extensively used for the interpretation of the Raman-Brillouin measurements, the connection between both models still needs to be clarified.…”