Autor(es): Rodrigues, Joana ; Peres, Marco ; Fernandes, António ; Graça, Manuel ; Sobolev, Nicolai ; Costa, Florinda ; Monteiro, Teresa
Data: 2011
Identificador Persistente: http://hdl.handle.net/10773/5519
Origem: RIA - Repositório Institucional da Universidade de Aveiro
Assunto(s): EPR; LFZ; PL; TiO2
TiO2 fibres grown by the laser floating zone technique show the rutile crystalline phase as identified by X-ray diffraction and Raman spectroscopy. Scanning electron microscopy evidences a uniform surface, free of inclusions and without low-angle grain boundaries and bubbles. At low temperatures, the fibres luminescence is dominated by a richly structured optical centre with two well-defined zero-phonon lines at 1.579 eV and 1.574 eV followed by an intense vibronic sideband with a maximum close to 1.47 eV. Electron paramagnetic resonance revealed that substitutional chromium and iron ions are present as contaminants in the grown fibres, alongside with Ti3+ interstitials and other structural defects. The chemical nature of the defect responsible for the structured near-infrared luminescence is discussed.
