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Optical parameters induced by phase transformation in RF magnetron sputtered TiO2 nanostructured thin films
Title
Optical parameters induced by phase transformation in RF magnetron sputtered TiO2 nanostructured thin films.
Creator
Nair, Prabitha B., Justinvictor, V.B., Daniel, Georgi P., Joy, K., James Raju, K.C., Kumar, David D., Thomas, P.V.
Abstract/Description
Pure TiO2 thin films were deposited onto quartz substrates using a ceramic TiO2 target at an elevated substrate temperature of 573 K by RF magnetron sputtering,and an analysis of structural, optical and photoluminescence characteristics of the films upon phase transformation is reported in this paper. Structural investigations using X-ray diffraction revealed that the as-deposited film was amorphous in nature. Thermal annealing for 2 h at 873 K in air resulted in the formation of anatase...
Show morePure TiO2 thin films were deposited onto quartz substrates using a ceramic TiO2 target at an elevated substrate temperature of 573 K by RF magnetron sputtering,and an analysis of structural, optical and photoluminescence characteristics of the films upon phase transformation is reported in this paper. Structural investigations using X-ray diffraction revealed that the as-deposited film was amorphous in nature. Thermal annealing for 2 h at 873 K in air resulted in the formation of anatase phase, and a phase transformation to rutile was observed at 1073 K. An increase in grain size and an improvement in crystallinity were also observed on annealing. Rod-like rutile crystallites were observed in the SEM images of the film annealed at 1273 K. As-deposited films and films annealed up to 1073 K were highly transparent in the visible region with a transparency >80%. Optical band gap of the films decreased upon thermal annealing which is attributed to phase transformation from amorphous to anatase and then to rutile. Optical parameters such as refractive index, optical conductivity and optical dielectric constant increased with increase in annealing temperature. Since rutile is the optically active phase, the superior refractive index of the film annealed at 1073 K along with its high transparency invisible region suggests the application of this film in antireflective coatings. Photoluminescence emission of maximum intensity was observed for the film annealed at 873 K, which exhibits anatase phase. Intense blue emission observed in this film makes it suitable for use in optoelectronic display devices.
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Date Issued
2014-06
PURL
http://purl.flvc.org/fau/fd/FAUIR000030
Format
Citation
Structural, optical, photoluminescence and photocatalytic investigations on Fe doped Tio2 thin films
Title
Structural, optical, photoluminescence and photocatalytic investigations on Fe doped Tio2 thin films.
Creator
Nair, Prabitha B., Justinvictor, V.B., Daniel, Georgi P., Joy, K., Ramakrishnan, V., Kumar, David D., Thomas, P.V.
Abstract/Description
Pure and Fe doped TiO2 thin films were deposited onto quartz substrates maintained at room temperature by radio frequency magnetron sputtering. The films were annealed at 873 K in air for 2 h and characterized using X-ray diffraction (XRD), micro Raman spectroscopy, Scanning electron microscopy (SEM), Energy dispersive spectroscopy, ultraviolet-visible and photoluminescence (PL) spectroscopy. Pure TiO2 thin films were XRDamorphous, but micro Raman spectra revealed the presence of anatase...
Show morePure and Fe doped TiO2 thin films were deposited onto quartz substrates maintained at room temperature by radio frequency magnetron sputtering. The films were annealed at 873 K in air for 2 h and characterized using X-ray diffraction (XRD), micro Raman spectroscopy, Scanning electron microscopy (SEM), Energy dispersive spectroscopy, ultraviolet-visible and photoluminescence (PL) spectroscopy. Pure TiO2 thin films were XRDamorphous, but micro Raman spectra revealed the presence of anatase phase. Doping with Fe has influenced the transformation of films to anatase phase. Improved crystallinity was observed in the 0.1 at% Fe doped films, where the lattice constants approached the values for bulk anatase TiO2, and the films showed minimum strain. At higher Fe concentrations, micro Raman spectra revealed the presence of rutile phase also. SEM images revealed crack free surface and surface roughness was found to increase with increase in Fe concentration. Dopingwith Fe has resulted in a red shift of absorption edge. PL emission intensitywas found to increase with Fe concentration, but at higher concentrations quenching of PL emission was observed. Fe doping resulted in enhancement of photocatalytic activity, evaluated by monitoring the degradation of methylene blue solution. 0.8 at% Fe doped TiO2 films exhibited the highest photocatalytic activity.
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Date Issued
2014-01
PURL
http://purl.flvc.org/fau/fd/FAUIR000031
Format
Citation