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Chemical bath deposition (CBD) technique was used for the synthesis of the Nickel Sulphide (NiS) thin films. The prepared NiS thin films were found to be polycrystalline and the crystals had hexagonal structure as revealed in the X-ray diffraction (XRD) analysis. The surface morphology of these films was studied by means of scanning electron microscopy (SEM). The optical properties of the NiS thin films were determined using UV-Visible absorption spectrum. The electrical studies were carried out at different frequencies and at different temperatures for the prepared NiS thin films. Further, electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability of the NiS thin films were calculated. The AC electrical conductivity measurements revealed that the conduction depended on both the frequency and the temperature. Photoconductivity measurements were carried out to reveal the positive photoconductivity of the NiS thin films. [ABSTRACT FROM AUTHOR]

Abstract: Gallium nitride (GaN) nanocrystals were synthesized by nitridation of Ga-EDTA (ethylene diamine tetra acetic acid) complexes at different temperatures starting from 600 to 900°C. X-ray diffraction analysis, Fourier transform infrared spectroscopy and Raman studies revealed that the compound synthesized at 900°C consists of single-phase GaN nanocrystals with wurtzite structure. The change in morphology of the GaN crystals at different temperatures was observed using scanning electron microscopy. The transmission electron microscopy showed the average size of the crystalline particles to be ∼20nm. The room temperature photoluminescence exhibits band-edge emission of GaN at 3.46eV for all the samples. The present study demonstrates that the nitridation of Ga-EDTA complex method has significant potential for the synthesis of GaN nanocrystals as a simple and inexpensive method. [Copyright &y& Elsevier]