Inhomogeneous broadening in the photoluminescence spectrum of CdS nanoparticles

The effect of particle size distribution of CdS nanoparticles on the band-e dge photoluminescence (PL) spectrum is investigated. The resulting inhomoge neously broadened lineshape is found to be asymmetric and depend on the wid th of particle size distribution. The calculated lineshape is fitted to the measured PL spectrum of 3.6 nm diameter CdS nanoparticles, which showed th e band-edge PL peak around 3.00 eV and that due to recombination at defects at 2.56 eV. The parameters of the PL spectrum of a bulk CdS film are used as inputs for the fitting. The average panicle size and the standard deviat ion of the size distribution are obtained from the analysis. The particle s ize estimated from the PL data is compared with that obtained from x-ray di ffraction measurements. (C)1999 Acta Metallurgica Inc.