Photocatalytic activity of dc magnetron sputter deposited amorphous TiO2 thin films

Eufinger, Karin; Poelman, Dirk; Poelman, Hilde; Gryse, Roger De; Marin, Guy

doi:10.1016/j.apsusc.2007.07.009

Cited by 132 publications

(88 citation statements)

References 15 publications

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“…This means that thickness of several hundreds nm is sufficient to achieve high values of the PCA for TiO 2 films sputtered at T surf = 180 8C. This finding agrees well with results obtained by Eufinger et al [16], who reported that the saturation of the PCA exhibit the films with h = 300-350 nm. The shift of the saturation of the PCA to higher h in our study can be explained by changes in phase composition of the film during its low-temperature growth.…”

Section: Effect Of Film Thicknesssupporting

confidence: 92%

“…Among many deposition methods [7][8][9][10][11][12][13][14], the magnetron sputtering is very promising one for the large-area deposition of thin, high quality, photoactive, crystalline anatase TiO 2 films at low values of T surf 200 8C [4,7,[13][14][15][16]. However, the deposition of crystalline photoactive TiO 2 films without the substrate heating or a post-deposition thermal annealing has not been fully mastered yet [12][13][14][15][16][17][18]. www Recently, it has been shown, that the magnetron sputtering of crystalline TiO 2 films with anatase structure at low values of T surf and without the high temperature post-deposition annealing is possible only in the oxide mode of sputtering [13,14,19].…”

Section: Introductionmentioning

confidence: 99%

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Nanostructure of photocatalytic TiO2 films sputtered at temperatures below 200°C

Šícha

Musil

Meissner

et al. 2008

Applied Surface Science

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Section: Effect Of Film Thicknesssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Nanostructure of photocatalytic TiO2 films sputtered at temperatures below 200°C

Šícha

Musil

Meissner

et al. 2008

Applied Surface Science

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“…S1) are included in Supporting Information]. This value of the bandgap is in good agreement with previously reported values for amorphous TiO 2 (22). Our TiO 2 films also exhibit surface roughness that is much smaller than the incident wavelength, as characterized by atomic force microscopy (AFM).…”

supporting

confidence: 76%

Broadband high-efficiency dielectric metasurfaces for the visible spectrum

Devlin

Khorasaninejad

Chen

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

467

361

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Metasurfaces are planar optical elements that hold promise for overcoming the limitations of refractive and conventional diffractive optics. Original dielectric metasurfaces are limited to transparency windows at infrared wavelengths because of significant optical absorption and loss at visible wavelengths. Thus, it is critical that new materials and nanofabrication techniques be developed to extend dielectric metasurfaces across the visible spectrum and to enable applications such as high numerical aperture lenses, color holograms, and wearable optics. Here, we demonstrate high performance dielectric metasurfaces in the form of holograms for red, green, and blue wavelengths with record absolute efficiency (>78%). We use atomic layer deposition of amorphous titanium dioxide with surface roughness less than 1 nm and negligible optical loss. We use a process for fabricating dielectric metasurfaces that allows us to produce anisotropic, subwavelength-spaced dielectric nanostructures with shape birefringence. This process is capable of realizing any high-efficiency metasurface optical element, e.g., metalenses and axicons.devices composed of subwavelength-spaced units and near-flat profiles compared with refractive optics (7-9)-have allowed unprecedented control over optical wavefronts (5) while circumventing Ohmic losses associated with plasmonic metasurfaces. Due to the scientific and technological importance of visible wavelengths, there has been increasing effort to realize DMs at these wavelengths. For example, silicon nitride DMs have been realized at a red wavelength (λ = 633 nm) (10), scattering properties of coupled TiO 2 resonators (11) have been examined, and TiO 2 binary diffraction gratings have been fabricated via top-down etching (12). However, no current DM implementation has been capable of providing arbitrary phase control of an optical wavefront while maintaining high efficiency across the entire visible spectrum (especially at blue and green wavelengths). Furthermore, the typical top-down techniques used to implement these metasurfaces can introduce significant surface roughness and make it difficult to create subwavelength sampling of a desired optical phase profile.In this paper, we demonstrate amorphous TiO 2 metasurfaces that maintain high efficiency across the entire visible spectrum. Our approach to creating DMs uses a bottom-up nanofabrication via atomic layer deposition providing high-aspect ratio, anisotropic dielectric nanostructures with minimal surface roughness. As proof of the concept that we can provide control of the phase of a wavefront from 0 to 2π, a requirement for many optical components, we produced metasurface holograms based on geometric phase. Efficient metasurfaces with metallic components operating in reflection have been demonstrated at red and nearinfrared wavelengths (13, 14) but have efficiencies of <1% and <10% at blue and green wavelengths, respectively (15, 16). Thus, the TiO 2 metasurfaces we demonstrate here provide substantial improvement with efficiencies fro...

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“…But, the rutile phase of TiO 2 is a desirable oxide phase for optical properties. Vacuumdeposited TiO 2 thin films with both anatase and rutile structure have been reported in the literature [5][6][7].…”

Section: Introductionmentioning

confidence: 98%

Cu/TiO2 thin films prepared by reactive RF magnetron sputtering

et al. 2015

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Cu/TiO 2 thin films were deposited on glass substrates by reactive RF magnetron sputtering technique. Crystalline structure, surface morphology and electronic structure were studied using X-ray diffraction (XRD), field emission scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). Transmittance and absorptance of these films were characterized by UV-Vis spectroscopy. XRD patterns demonstrate that TiO 2 films deposited on glass substrate at 300°C are observed to be in pure anatase phase, whereas Cu/TiO 2 films are amorphous in nature at 300°C substrate temperature. The crystallinity of Cu/TiO 2 thin films decreases with increasing the dopant concentrations of Cu in TiO 2 films. XPS studies show that Cu is in ?2 oxidation state in all films. The optical band gap of Cu/TiO 2 films decreases from *3.3 to *2.0 eV with the increase in the copper concentration. Further, antimicrobial studies of Cu/TiO 2 films with *3.9 at.% Cu exhibit high transmittance and best antimicrobial activity against E. coli and S. aureus compared to other doped films.

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Photocatalytic activity of dc magnetron sputter deposited amorphous TiO2 thin films

Cited by 132 publications

References 15 publications

Nanostructure of photocatalytic TiO2 films sputtered at temperatures below 200°C

Nanostructure of photocatalytic TiO2 films sputtered at temperatures below 200°C

Broadband high-efficiency dielectric metasurfaces for the visible spectrum

Cu/TiO2 thin films prepared by reactive RF magnetron sputtering

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