Effect of Deposition Time on Morphology and Optical Properties of Nanocrystalline CeO_2/CdS Thin Films Grown by Chemical Bath Deposition

摘要

CeO_2/CdS thin films were prepared using a two-step growth technique. The effect of deposition time on the morphology and optical properties of the CeO_2/CdS thin films were systematically studied. The morphology and composition of the CeO_2/CdS films deposited on FTO substrates were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum analysis (EDXA), respectively. The optical properties of the films were studied by UV-vis absorption and photoluminescence (PL) spectroscopy. The optical band gap values of the CeO_2/CdS films was found to be 2.13 - 2.45 eV as estimated from the UV-Vis absorption spectra. A strong blue emission band was observed in the room temperature photoluminescence spectrum for CeO_2/CdS thin films. The estimated lifetime from decay curve analysis shows enhanced lifetime for CeO_2/CdS films with an increase in deposition time. The enhanced absorbance and strong visible luminescence suggest its future application as energy conversion device and phosphor.