Studies on CdS nanoparticles dispersed in silica matrix prepared by sol-gel technique
Department of Materials Science, Indian Association for the Cultivation of Science,
Calcutta 700 032, India
Corresponding author: a email@example.com
Published online: 27 January 2003
SiO2/CdS-nanoparticle composite films (SiO2:CdS=85:15, 80:20, 75:25 and 70:30) were prepared by the sol-gel route. The films were characterized by studying microstructural (XRD and TEM) and optical (transmittance and photoluminescence) properties. Band gaps of these films annealed at different temperatures (373–473 K) for different times (10–120 min) indicated that the signature of nanocrystallinity is retained throughout the range of our experimental conditions. A thermal diffusion process controlled growth in the crystallite size with increasing annealing time and temperature. The average radii of the nanoparticles varied as the cube root of the annealing time but showed exponential dependence on the inverse of annealing temperature. Photoluminescence (PL) studies of the composite films indicated excitonic transitions. Theoretical analysis of the line shapes of the PL peaks recorded at 300 K and 80 K could be accounted for by the combined effects of size distribution and phonon broadening. It was observed that the deformation potential (Ed) effectively controlled the line shapes of the PL measurements.
PACS: 78.20.-e – Optical properties of bulk materials and thin films / 81.05.Dz – II-VI semiconductors
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003