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

Abstract

CdS nanoparticles, with an average diameter between 2.3 and 5.5 nm, were grown in phosphate glasses. The photoluminescence of the aforementioned materials 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 phenomenological spin Hamiltonian, revealed that the luminescence band is associated with a recombination between trapped electrons and holes, at asymmetric sites, more likely located at the surface of the nanoparticles. Moreover, this simulation showed a distribution of electron–hole distances around the circumference of the nanoparticles.