Effects of composition and structure on hydrogen incorporation in tungsten oxide films deposited by sputtering

Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Yoshikawa, Masahito; Shikama, Tatsuo*

The effects of composition and structure on hydrogen incorporation property in tungsten oxide films were investigated. The tungsten oxide was deposited on carbon and SiO substrates to form films by varying the temperature from 30 to 600 C using a reactive sputtering in argon and oxygen mixture. We obtained amorphous structure in the films deposited below 400 C and (0 1 0) oriented monoclinic WO in the films deposited beyond 400 C. Hydrogen concentration in the films increased from 0.1 to 0.7 H/W with changing the composition from WO to WO. The hydrogen concentration in WO films decreased to 0.4 H/W with increasing the substrate temperature during deposition. The Raman spectra of the WO films revealed that decreasing of W=O terminals was related to that of the hydrogen concentration. It was considered in detail that the incorporated hydrogen in tungsten oxide films was bonded at the end of W=O terminals.