O. Monnereau, L. Tortet, C. E. A Grigorescu, D. Savastru, CR Iordanescu, F. Guinneton, R. Notonier, A. Tonetto, T. Zhang, I. N. Mihailescu, D. Stanoi, H. J Trodahl, Chromium oxides mixtures in PLD films investigated by Raman spectroscopy, J. Optoelectron. Adv. Mater., 12/8 (2010) 1752 – 1757.

Title: Chromium oxides mixtures in PLD films investigated by Raman spectroscopy

Abstract: The composition of Pulsed Laser Deposited thin films from Cr(8)O(21) targets has been investigated by Raman spectroscopy. To this purpose we have prepared the chromium oxides Cr(8)O(2l), Cr(2)O(5), CrO(2) and Cr(2)O(3) in bulk form to provide standard Raman spectra for characterisation of the samples. The range of oxides has been prepared by thermal decomposition of CrO(3) following the thermo-gravimetric analysis. CrO(2) was obtained by two other specific ways, i.e. hot pressing of Cr(8)O(21) and hydrothermal synthesis. Structural characterization was performed by X-ray diffraction, SEM, IR and Raman spectroscopy, Raman investigation is demonstrated to have the capacity to identify CrO(2) as well as trace concentrations of secondary phases in the PLD thin films. The Raman measurements have led us also to the conclusion that PLD of Cr(8)O(21) targets yields in thin films containing either mixtures of (Cr(2)O(5), CrO(2) and Cr(2)O(3)) or, under particular conditions of oxygen pressure and substrate temperature, of (CrO(2) and Cr(2)O(3)) only.

Key words: Chromium oxides; PLD; Thin films; Raman spectroscopy; Chemical synthesis