Effects of Ion-Beam-Irradiation on Morphology and Densification of CeO 2 Films Prepared by Ion-Beam-Assisted Deposition

Kuniyoshi

Aoki

et al. 2008

jjap

Titanium dioxide (TiO 2 ) films were deposited by the oxygen plasma-assisted reactive evaporation (OPARE) method. TiO 2 films with an anatase structure were formed when activated oxygen plasma was supplied to the substrate during deposition, whereas the films with a rutile structure were formed when nonactivated oxygen gas was supplied. These results were explained by the promotion of the oxidization of titanium atoms by the supply of activated oxygen plasma, because the anatase film is obtained under conditions where sufficient oxidization of titanium atoms is achieved, and the rutile film is formed under the conditions where insufficient oxidization occurs. These results indicate that oxygen plasma assist is an effective method for promoting oxidization and reducing the amount of oxygen gas used in this method. Both films deposited with or without plasma assist at temperatures greater than 250 C exhibited ultra-hydrophilicity. These films also showed definition methylene-blue (MB) decomposition photocatalytic performance indexes in the range from 7.8 -11.9 mmolÁl À1 Ámin À1 . The described results indicate that the TiO 2 films obtained by this method exhibit adequate performance for photocatalytic applications.

Section: Introductionmentioning

confidence: 99%

Photocatalytic Characteristics of TiO₂ Films Deposited by Oxygen Plasma-Assisted Reactive Evaporation Method

Kuniyoshi

Aoki

et al. 2008

jjap

“…12) In this method, the vacuum evaporation of titanium (Ti) and oxygen ion irradiation are combined to obtain films with a high density and excellent crystal structure. [13][14][15][16][17] It is noteworthy that this method enables the precise control of the crystallographic structure of the films. No detailed study on the lowtemperature deposition of the film and its photocatalytic performance has been reported yet.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Characteristics and Structure of TiO₂Film Deposited by Oxygen-Ion-Assisted Reactive Evaporation at Low Temperature

Ikegaya

Ishihara

et al. 2010

Jpn. J. Appl. Phys.

Beginning with the Pauli-Fierz theory, we construct a model for multi-graviton theory. Couplings between gravitons belonging to nearest-neighbour 'theory spaces' lead to a discrete mass spectrum. Our model coincides with the Kaluza-Klein theory whose fifth dimension is latticized. We evaluate one-loop vacuum energy in models with a circular latticized extra dimension as well as with compact continuous dimensions. We find that the vacuum energy can take a positive value, if the dimension of the continuous spacetime is 6, 10, . . . . Moreover, since the amount of vacuum energy can be an arbitrary small value depending on the choice of parameters in the model, our models are useful for explaining the small positive dark energy in the present universe.

“…They include sol-gel, dip coat, binder, spray, thermal spray, sputtering, chemical vapor deposition, ion plating, and oxygen ion assisted reactive evaporation (OIARE) methods 4,5 . In the method, vacuum evaporation of titanium (Ti) and oxygen ion irradiation are combined to obtain a film with high density and excellent crystalline [6][7][8][9] . In our previous papers, we reported that the OIARE can not only realize very high deposition rate greater than 100 nm/min, but also deposit crystallized TiO 2 films at a low substrate temperature below 100 °C.…”

Section: Introductionmentioning

confidence: 99%

The relationships between the film structure and photocatalytic characteristics of TiO<sub>2</sub> films deposited under oblique incidence by oxygen ion assisted reactive evaporation (OIARE) method.

Trans. Mat. Res. Soc. Japan

Sato

Mochiduki

et al. 2009

We deposited the TiO 2 films at various oxygen ion accelerating voltages under oblique incidence by using OIARE method and investigated the relationships between their structures and photocatalytic performances. The films deposited at 350 °C, the accelerating voltage of 200 eV, and substrate tilt angle of 35 degree had excellent photocatalytic performance of 17.7 [µmol·l -1 ·min -1 ] for the decomposition of metylene-blue. The film has anatase structure with mean surface roughness Ra of 11.4 nm and mean crystallite size of 18.0 nm. The photocatalytic performance takes a maximum value around 200 eV and decreases monotonically with further increase of the accelerating voltage. The mean crystallite size of the film was decreased from 20.8 nm to 14.3 nm by the increase of the oxygen ion accelerating voltage from 0 to 1000 eV, which suggests that the high energy oxygen ion bombardment to the film surface will produce damages in the film and degrading the performance of the film. These results indicate that control of the energy of oxygen ions incident to the film surface is important to obtain a film with excellent photocatalytic properties.