Structural and optical studies of CdS nanocomposites synthesized by various routes

Structural and optical properties of CdS nanocomposites prepared by two different routes are presented in this paper. While CdS prepared by aqueous media results in the formation of nanoparticles of particle sizes 8-9 nm; the solvothermal process results in the formation of nanorods of diameter 40-50 nm and length 450-750 nm where particle sizes were confirmed by SEM and TEM. XRD studies confirm that the structure of these nanocomposites is wurzite. EDAX give the stoichiometric ratio. UV-Vis and photoluminescence (PL) measurements show a blue shift compared to bulk CdS, supporting quantum confinement effect. Nanocomposites are found to be stable up to 650 degrees C was observed by thermo gravimetric analysis (TGA). The Raman scattering studies show that in addition to LO and TO phonon modes, peak corresponding to surface phonon modes are present in both cases, which are due to high surface to volume ratio. The CdS nanocomposites can therefore be used for various stable optoelectronic devices.