Analysis of TihxOy Films Produced by Physical Vapor Deposition Method

For decades, partially oxidized hydrides were commonly considered as undesirably contaminated phases and were avoided by scientists. Nevertheless, more recently, it was realized that in some hydrides and oxides, partial substitution of dissimilar H− and O2− anions allows one to obtain unique optical and electrical properties that might have appealing applications in commercial products. It was determined that specific properties of so called oxyhydride materials strongly depend on the used synthesis methods; therefore, there is a great interest in exploring various variants of oxyhydride formation. In the current study, TiHxOy films were deposited by a reactive magnetron sputtering process in Ar-O2-H2 gas mixtures. Color, transparency and crystal phase composition of the films coherently reacted to the Ar:O2:H2 gas ratio. Namely, the rise in partial hydrogen pressure promoted the formation of anatase phase TiO2 structure and darkening of the films. Interestingly, this had only minimal impact on the band gap values, but had a relatively strong negative effect on the photocatalytic activity of the films. The unaccustomed results stressed the difference between the partially reduced TiO2 with a significant amount of oxygen vacancies and synthesized TiHxOy films where some O2− ions are implicitly substituted by H− ions.