Effects of Sputtered High-Energy Particles on the Structure and Photocatalytic Performance of TiO₂ Films Prepared by a DC Reactive Sputtering Method

Abstract

By using the Kevin–Meyer formula, we calculated the energy of the high-energy particles (recoil argon ions and negative oxygen ions) that are unique to sputtered thin-film formation when they arrived at a substrate during the sputtering process. We found that the energy of the high-energy particles arriving at the substrate decrease if total gas pressure increases, whereas the photocatalytic performance of a TiO2 film increases if the total gas pressure increases. We also found that as total gas pressure increases, the surface morphology changed from a gap-free structure to a porous structure in which subgrains were observed. Accordingly, the average surface roughness (R a) and surface area (S) of the thin film increased. The number of defects, mainly oxygen defects, in the forbidden band also changed depending on the energy of the high-energy particles. Therefore, it was found that the high-energy particles affect the surface area of the TiO2 thin films and the formation of defects in the thin films, which consequently influences the photocatalytic performance.

High-rate deposition of photocatalytic TiO2 films by oxygen plasma assist reactive evaporation method

“…While on the other hand, the index for glass substrate was 1.6 [μmol l − 1 min − 1 ]. These results indicate that our films, deposited at such a high deposition rate, have similar MB decomposition performance to that of films obtained using reactive sputtering method [15][16][17].…”

Constitution, microstructure, and battery performance of magnetron sputtered Li–Co–O thin film cathodes for lithium-ion batteries as a function of the working gas pressure

“…2(d)) the energy of the sputtered high-energy particles is again several times lower than for the 10 Pa sample. This can be estimated by the Kevin-Meyer formula [11,12]. Noguchi et al reported that if the gas pressure increases the energy of the high-energy particles arriving at the substrate decreases and the surface morphology of TiO 2 films changes from a gap-free structure to a porous structure.…”

Photoinduced Hydrophilicity and Structural Evaluation of SiOx:OH/TiO2 Multilayer Films by DC Reactive Magnetron Sputtering

“…TiO 2 thin films were fabricated by DC reactive magnetron sputtering using parameters with which we had already successfully obtained highly reactive photocatalytic characteristics, as reported previously. 14,15) Shigesato's group has also reported on the use of reactive sputtering to deposit TiO 2 thin films. 16,17) They succeeded in fabricating highly reactive photocatalytic thin films by sputtering under a wide range of conditions, including differing intensities and shapes of magnetic field.…”