Um novo método para síntese de vidros fotônicos baseado na sinergia entre as técnicas VAD e ALD / A new method for synthesis of photonic glasses based on the synergy between VAD and ALD techniques

AUTOR(ES)

Tarcio Pelissoni Manfrim

DATA DE PUBLICAÇÃO

2011

RESUMO

This study aimed to establish a new method for synthesis of photonic glasses through the synergy of Vapor-phase Axial Deposition (VAD) and Atomic Layer Deposition (ALD) techniques. Having the intention to obtain a completely transparent material containing a uniform distribution of dopant element both radial and axial position. In the first stage of this study it was designed, built and tested an ALD reactor of laboratory scale appropriate for doping of VAD porous preforms. The subsequent stage included the manufacture of pure silica porous preform by VAD technique, doping with titania by ALD technique and consolidation in an electric furnace to obtain the final material in glassy state. The effect of variation of parameters of VAD and ALD processes on structural and optical properties of the material was studied. The structural properties were characterized by X-ray fluorescence spectrometry, X-ray diffraction and Raman spectroscopy. The optical properties were determined using optical absorption spectroscopy. Greater uniformity of the dopant (TiO2) have been achieved through doping carried out under high temperature, since it was possible to avoid the effect of condensation of the precursors. Furthermore, porous preforms with higher average density showed a greater tendency to form a more constant doping profile. For samples doped at 90 °C, the doping rate was approximately 0.75 wt% of TiO2/cycle for the first 4 ALD cycles. Samples of SiO2-TiO2 showed a maximum optical transmittance in the infrared and visible very similar to that of pure silica, suffering an abrupt absorption near the UV range due to formation of titanium atoms with valence 4+

ASSUNTO(S)

sílica vitreo dióxido de titânio nanopartículas sinterização vitreous silica titanium dioxide nanoparticles sintering

Documentos Relacionados

• AN ARCHITECTURE FOR PHOTOREALISTIC IMAGE SYNTHESIS BASED ON MONTE CARLO TECHNIQUES
• Desenvolvimento de técnica para nucleação de nanopartículas metálicas em vidros de germanato dopados com íons de túlio para aplicações em dispositivos fotônicos.
• Silica vitrea de alto desempenho óptico produzida por método de aerosol em chama para componentes fotônicos
• Characterization of silver nanostructures in tellurite glasses for photonic applications.
• Sinergia entre sistemas imunologicos artificiais e modelos graficos probabilisticos