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 °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.