Fabrication of Co- and Ce-doped ZnO nanoparticles: a structural, morphological and optical properties investigation

We have analysed the effect of co-doping Rare Earth (Ce) and Transition metal (Co) on optical properties in ZnO nanoparticles. We have prepared 1 at %, 2 at % and 3 at % Ce and Co co-doped ZnO nanoparticles annealed at 600 °C, 700 °C, and 800 °C temperatures by simple sol–gel method using ethanol as a solvent. The structural and morphological properties were characterized by XRD (X-ray Diffraction), RAMAN and SEM (Scanning Electron Microscopy), respectively. All the prepared samples were polycrystalline and wurtzite in structure, showing that Ce and Co have been successfully incorporated into the wurtzite crystal structure of ZnO. Particles were uniformly distributed and the calculated average crystallite size was in the range of 50–100 nm. There was no large shift in the XRD spectra. For optical properties PL (Photoluminescence) spectroscopic and UV–Visible spectroscopic techniques were used. We have obtained two sharp peaks in the PL spectra nearly at 510 and 612 nm. 510 nm emission may be due to trap-state, deep-level emission, whereas, 612 nm emission was due to either charge transfer (CT) transition between O−2 and Ce+4 ion. These two emission peaks were stable with respect to doping concentration upto 2%. The results show that this method produce perfectly co-doped ZnO nanoparticles having sharp emission spectra, so that we can use these materials in LEDs and photodetectors.