Camarillo, E. and Murrieta, H. and Hernandez, J.M. and Zoilo, R. and Flores, M.C. and Han, T.P.J. and Jaque, F. (2008) Optical properties of LiNbO3 : Cr crystals co-doped with Germanium oxide. Journal of Luminescence, 128 (5-6). pp. 747-750. ISSN 0022-2313Full text not available in this repository. (Request a copy from the Strathclyde author)
Lithium niobate (LiNbO3) crystals doped with chromium ions show a clear green colouring reflecting the absorption profile of the dominating [Cr](Li) defect centres. A significant change in its colouration takes place when it is co-doped with other valency impurities such as Mg2+, Sc3+ and W6+, above a certain threshold concentration. This concentration singularity has been attributed to the formation of [Cr](Nb) centres coexisting with the [Cr](Li) centres. In this work, we extended the investigation on the effect of co-dopant ions in Cr:LiNbO3 to tetravalent cation such as GeO2. A singularity in the relative intensity of the (4)A(2)-> T-4(1) and (4)A(2)-> T-4(2) absorption band was observed for a concentration of similar to 1.5 mol%, compared with 4.5 mol% for Mg2+. The photoluminescence emission spectra also reveal a new emission band, at a lower energy than the [Cr](Li) centre, corresponding to this threshold concentration. A charge compensation model is proposed to explain the role of cation impurities and results are compared with those of other valence impurities.
|Keywords:||absorption, luminescence, Cr, Ge, LiNbO3, Solid state physics. Nanoscience, Biochemistry, Biophysics, Atomic and Molecular Physics, and Optics, Chemistry(all), Condensed Matter Physics|
|Subjects:||Science > Physics > Solid state physics. Nanoscience|
|Department:||Faculty of Science > Physics|
|Depositing user:||Strathprints Administrator|
|Date Deposited:||08 Jun 2010 09:35|
|Last modified:||06 Jan 2017 07:39|