Synthesis and characterization of CdS nanocrystals embedded in germanate glasses

Abstract

Cadmium sulfide nanoparticles were grown in Na 2 O-GeO 2 glass matrix by a diffusion-controlled phase decomposition of over-saturated solid solution. The structural properties of CdS nanocrystals have been studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), optical absorption and electrical conductivity. The existence of CdS nanocrystals was confirmed by XRD and TEM, also its crystallite sizes are obtained. The average CdS crystallite sizes calculated from XRD analysis for the different heat-treatment conditions are found in the range between 23.7 and 48.8 nm; however, the average CdS crystallite sizes obtained from TEM micrographs are found in the range between 17 and 63 nm. The band gap energy E opt and the activation energy E g for the electrical conductivity have been increased with decrease in the particle size; however, the Urbach energy DE decreases with decreasing the nanocrystal size.

Novel PbSe nanocrystals doped fluorogermanate glass matrix

“…7). The low rate of changing the band gap at these temperatures may be due to the reduction of intrinsic defects at the nanoparticles glass interface [29][30][31][32]. Then the obtained results imply that the increase in nanoparticle size with increasing annealing temperature leads to a decrease in the band gap energy.…”