Surface chemistry of H2S-sensitive tungsten oxide films

✍ Scribed by B. Frühberger; M. Grunze; D.J. Dwyer

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 687 KB
• Volume: 31
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(96)80062-1

✦ Synopsis

We have applied X-ray photoelectron spectroscopy (XPS) arid ultraviolet photoelectron spectroscopy ( UPS ) ~o characterize t'lin tungsten oxide films and to investigate their interaction with hydrogen sulfide in view of their use as very sensitive hydrogen sulfide gas sensors. W 4f core-level spectra indicate a partial reduction of W ~ + after the ~eaction. No evidence for band bending after H2S dosing could be found in the valence-band spectra. The results suggest that the primary sensing mechanism involves the formation of oxygen vacancies on the surface in the presence of hydrogen sulfide. Alternative mechanisms, such as the formation of a tungsten sulfide or a hydrogen tungsten bronze on the surface, are judged to be unlikely.