Keywords : optical band gap energy.&amp;nbsp
Advanced Materials Letters,
2015, Volume 6, Issue 4, Pages 354-358
Cadmium sulphide (CdS) nanostructured films were prepared by chemical bath deposition (CBD) method at room temperature. The prepared films were subjected to swift heavy ion (SHI) irradiation by using 100 MeV Si 8+ ion beams at various fluences from 1x10 11 to 1x10 13 ions/cm 2 . Structural, morphological, optical properties of the pristine and irradiated films were characterized by X-ray diffractrometer (XRD), high resolution transmission electron microscope (HRTEM), UV-Vis spectroscopy and Raman spectroscopy. XRD study confirms the formation of nanocrystalline cubic phase in all the films. The crystallite size is found to increase from 7nm to 9 nm and shift of peak positions are observed due to irradiation. The lattice strain and dislocation density of the samples are of the order of 10 -3 and 10 16 m -2 respectively and the values are found to decrease upon irradiation. HRTEM images show that the shapes of the particles are nearly spherical and the selected area electron diffraction (SAED) pattern of HRTEM have also supported the formation of cubic phase CdS. The optical absorption spectra exhibit shift in the fundamental absorption edge and the optical band gap decreases from 2.585eV to 2.513 upon SHI irradiation. Three intense Raman lines for pristine as well as irradiated CdS have been observed and all the samples show shift in Raman lines relative to bulk CdS due to phonon localization. The SHI irradiation on chemically deposited CdS films is an important tool used for modification of structural, morphological and optical properties of the films for possible applications in device fabrication.