| 1. |
- Jensen, Jens, et al.
(author)
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Localized 56Fe+ ion implantation of TiO2 using anodic porous alumina
- 2009
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In: Ion Beams and Nano-Engineering. - Warrendale, PA, USA : Materials Research Society. - 9781605111544 ; , s. 3-8
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Conference paper (peer-reviewed)abstract
- We present result following localized ion implantation of rutile titanium dioxide (TiO2) using anodic porous alumina as a mask. The implantation were performed with 100 keV 56Fe+ ions using a fluence of 1.3·1016 ions/cm2. The surface modifications where studied by means of SEM, AFM/MFM and XRD. A well-defined hexagonal pattern of modified material in the near surface structure is observed. Local examination of the implanted areas revealed no clear magnetic signal. However, a variation in mechanical and electrostatic behavior between implanted and non-implanted zones is inferred from the variation in AFM signals.
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| 2. |
- Rivera, Antonio, et al.
(author)
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On the Exciton Model for Ion-Beam Damage: The Example of TiO2
- 2010
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In: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 268, s. 3122-3126
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Journal article (peer-reviewed)abstract
- The non-radiative exciton decay model recently developed to account for swift ion-beam damage toLiNbO3 is, here, discussed within a general physical perspective, taking previous work on alkali halides as a reference. Some general rules for the validity of excitonic models have been put forward, allowing one to predict the irradiation behaviour of other materials. As a new example of application, some preliminary data on the generation and growth of uniform amorphous layers induced by irradiation with Br at 13 MeV and 25 MeV have been performed on rutile (TiO2). In addition sub-threshold irradiations with Br ions at 9 MeV have been carried out. Defects generation is observed as a result. This effect is explained with the exciton model. Experiments are in the electronic excitation regime and use moderate fluences in the range of 6 x 1012 to 1.5x 1014 cm-2. The results show similar features to those found for LiNbO3 and are, in principle, consistent with a non-radiative exciton decay model.
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| 3. |
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| 4. |
- Sanz, Ruy, et al.
(author)
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Fabrication of Well-Ordered High-Aspect-Ratio Nanopore Arrays in TiO2 Single Crystals
- 2006
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In: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 6:5, s. 1065-1068
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Journal article (peer-reviewed)abstract
- In this work a successful method for producing high-aspect-ratio nanopatterned single-crystal TiO2 is presented. The method used is based on nanolithography involving swift heavy ion bombardment through a porous anodic alumina mask. Nanopatterning of large areas allows for fabrication of new devices, for example, photonic crystals and electrodes for energy storage and conversion. Crystalline TiO2 also presents optimal characteristics for optical and catalysis applications. Samples were irradiated by MeV Br7+ ions with fluencies ranging from 7.9 × 1013 to 1.2 × 1015 cm-2. The high-energy Br7+ ions induce latent tracks of amorphous material into the TiO2 crystal suitable for selective etching by hydrofluoric acid. High-aspect-ratio (16) nanopatterned areas, up to 4 mm2, were obtained in a single radiation spot onto single-crystalline TiO2.
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| 5. |
- Sanz, Ruy, et al.
(author)
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UV-black rutile TiO2: An antireflective photocatalytic nanostructure
- 2015
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In: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 117:7, s. 074903-
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Journal article (peer-reviewed)abstract
- This work presents an experimental study on the specific quantitative contributions of antireflective and effective surface areas on the photocatalytic and antibacterial properties of rutile TiO2 nanospikes. They are studied when continuously distributed over the whole surface and when integrated into well-defined microstructures. The nanospikes were produced following MeV ion beam irradiation of bulk rutile TiO2 single crystals and subsequent chemical etching. The ion beam irradiation generated embedded isolated crystalline nanoparticles inside an etchable amorphous TiO2 layer, and nanospikes fixed to the not etchable TiO2 bulk substrate. The produced nanospikes are shown to resist towards aggressive chemical environments and act as an efficient UV antireflective surface. The photocatalytic activity experiments were performed under the ISO 10678: 2010 protocol. The photonic and quantum efficiency are reported for the studied samples. The combined micro-and nanostructured surface triples the photonic efficiency compared to the initial flat surface. Results also revealed that the antireflective effect, due to the nanostructuring, is the dominating factor compared to the increase of surface area, for the observed photocatalytic response. The obtained results may be taken as a general strategy to design and precisely evaluate photoactive nanostructures. (C) 2015 AIP Publishing LLC.
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| 6. |
- Sanz, Ruy, et al.
(author)
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Well-ordered nanopore arrays in rutile TiO2 single crystals by swift heavy ion-beam lithography
- 2007
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In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 18:30, s. 305303-
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Journal article (peer-reviewed)abstract
- Ion track lithography has been applied for transferring the self-ordered nanopattern of porous anodic alumina to single-crystalline rutile TiO2 substrates. As a result, nanometre resolved arrays have been fabricated with an aspect ratio ranging from 5 to 16, over areas of several square millimetres. Differences in the expected aspect ratio of the resulting nanopores in rutile TiO2 single crystals are analysed and discussed. Some of these differences may be ascribed to varying densities of the mask material.
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| 7. |
- Skupinski, Marek, et al.
(author)
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Surface Patterning by Heavy Ion Lithography Using Self-Assembled Colloidal Masks
- 2007
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In: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 257:1-2, s. 777-781
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Journal article (peer-reviewed)abstract
- Heavy ion lithography using self-assembled colloidal particles as a mask enables micro- and nano-patterning of surfaces. The resulting patterns can be tuned by varying the mask configuration, i.e. packing geometry of the colloidal particles and number of particle layers. In this work we present several patterns, which can be transferred to rutile TiO2 single crystals by irradiating through self-assembled layers of silica micro-spheres with 25 MeV Br ions. As the induced ion tracks in TiO2 have a very high etching selectivity the patterns can be developed in HF with very high contrast. This makes it possible to prepare large patterned areas which can be of interest for e.g. optical applications.
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