Synthesis, structural and optical characterization of nanocrystalline ternary image thin films by chemical process

Cd1-xZnxS nanocrystalline thin films with different compositions (0⩽x⩽1) were successfully synthesized by a simple wet chemical route without using any capping agent or surfactants on the glass substrates. X-ray diffraction study showed the proper cubic phase formation. Due to the increase of Zn content into the film, all the peaks shifted towards the higher diffracting angles. The lattice constant also gradually decreased as Zn content increased. Transmission electron micrograph showed the presence of uniform spherical particles and particle sizes varied from 3 to 5 nm as Zn content increased. Optical studies revealed that the transmittance increased and reflectance decreased with the increase of Zn content. The strong absorption edge also shifted towards the lower wavelength region and hence the band gap of the materials increased with the increase of Zn content. Due to the quantum confinement of the carriers in the nanoparticles the band gap energy was higher than the corresponding bulk materials. The photoluminescence emission peaks continuously shifted towards the lower wavelength region i.e. blue-shift occurred with the increase of Zn contents.