Microstructural and photoluminescence properties of Co-doped ZnO films fabricated using a simple solution growth method

Nanocrystalline 2% cobalt doped ZnO films were successfully prepared using a simple chemical solution method on glass substrates and subsequently annealed in air at 300 and 500 degrees C. Structural, morphology, chemical composition and photoluminescence properties of the films were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and Fourier transform infra-red spectroscopy (FTIR) and photoluminescence (PL) spectroscopy. X-ray diffraction studies of the annealed films reveal the formation of polycrystalline hexagonal wurtzite structure of ZnO crystals without any co-related secondary phases. SEM micrographs of the films show the formation of spherical nanoparticles. Photoluminescence of the films showed a weak UV and defect related visible emissions like blue, blue-green, yellow and relatively intense orange-red emissions and their mechanism was discussed in detail. (C) 2010 Elsevier Ltd. All rights reserved.