Optical, X-ray absorption and photoelectron spectroscopy investigation of the Co site configuration in Zn 1− x Co x O films prepared by pulsed laser deposition

• Published in: Superlattices and microstructures Vol. 42; no. 1; pp. 226 - 230
• Main Authors: Sans, J.A., Sánchez-Royo, J.F., Pellicer-Porres, J., Segura, A., Guillotel, E., Martinez-Criado, G., Susini, J., Muñoz-Páez, A., López-Flores, V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2007
• Subjects: EXAFS; Optical absorption; Reflexafs; Site configuration; XANES; XPS; ZnCoO; Reflexafs; Site configuration; XANES; ZnCoO; XPS; EXAFS; Optical absorption
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2007.04.065

In this paper, we investigate the Co site configuration in Zn 1− x Co x O thin films by means of different spectroscopic techniques. Thin films were prepared by pulsed laser deposition with Co proportion from 1% to 30%. The Co 2p doublet observed in the X-ray photoelectron spectra exhibits the spin–orbit splitting and shake-up satellites typical of Co +2 ionization states. X-ray absorption spectra at the Co K-edge, taken in fluorescence mode, unambiguously show that Co atoms are in tetrahedral configuration substituting for Zn over the whole composition range. Optical absorption spectra provide further evidence of the tetrahedral coordination of Co cations, both through the internal transitions in the Co 3d shell and through the shift to higher energies of the band-to-band absorption edge with the increase of the Co proportion.