Electronic structure of Co-doped ZnO nanorods Electronic structure of Co-doped ZnO nanorods (original) (raw)

Electronic structures and magnetism of diluted magnetic semiconductors Sn1−xGdxTe: A density functional theory study J. Appl. Phys. 112, 083720 (2012) Cylindrical coordinate representation for multiband Hamiltonians J. Appl. Phys. 112, 084319 (2012) Hard x-ray photoelectron spectroscopy study on band alignment at poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)/ZnO interface APL: Org. Electron. Photonics 5, 237 (2012) Hard x-ray photoelectron spectroscopy study on band alignment at poly(3,4ethylenedioxythiophene):poly(styrenesulfonate)/ZnO interface Appl. The optical transmission spectra, the photoluminescence (PL), and the photoluminescence excitation (PLE) spectra of the cobalt doped zinc oxide nanorods Zn 1Àx Co x O (x ¼ 0.01, 0.10) were measured by Loan et al. [J. Phys. D: Appl. Phys. 42, 065412 (2009)] in the region 1.5-4 eV. These spectra exhibit a group of ultraviolet narrow lines in the region of 3.0-3.4 eV related to the nearband-edge emission of the host ZnO materials and a group of emission lines in the red region of 1.8-1.9 eV assigned to the radiative transitions within the tetrahedral Co 2þ ions in the ZnO host crystal. The group of lines in the visible region provides important information about the electronic structure of the cobalt doped zinc oxide nanorods. This work investigates a theoretical crystal-field analysis of the visible lines associated to the Co 2þ ion transition occupying a T d site symmetry in ZnO host crystal. A satisfactory correlations were obtained between experimental and calculated energy levels. The electronic structure was compared with the reported for cobalt transition ion doped in ZnO nanoparticles and bulk crystals [Volbers et al., Appl. Phys. A 88, 153 (2007) and H. J. Schulz and M. Thiede, Phys. Rev. B 35, 18 (1987)]. In order to explain the existence of excitation peaks observed near the band edge of the ZnO host, an energy transfer mechanism is proposed.