Optically detected magnetic resonance studies of CdS nanoparticles grown in phosphate glass

CdS nanoparticles, with an average diameter between 2.3 and 5.5 nm, were gr own in phosphate glasses. The photoluminescence of the aforementioned mater ials showed a broad band, Stokes shifted from the corresponding absorption edge by about 1.2 eV and blue shifted upon reduction of the particle size. The ODMR spectra of the discussed materials are composed of three resonance signals. Theoretical simulation of the latter spectra, utilizing phenomeno logical spin Hamiltonian, revealed that the luminescence band is associated with a recombination between trapped electrons and holes, at asymmetric si tes, more likely located at the surface of the nanoparticles. Moreover, thi s simulation showed a distribution of electron-hole distances around the ci rcumference of the nanoparticles. (C) 1999 Published by Elsevier Science B. V. All rights reserved.