D. Davazoglou et K. Georgouleas, LOW-PRESSURE CHEMICALLY VAPOR-DEPOSITED WO3 THIN-FILMS FOR INTEGRATEDGAS SENSOR APPLICATIONS, Journal of the Electrochemical Society, 145(4), 1998, pp. 1346-1350
Citations number
16
Categorie Soggetti
Electrochemistry,"Materials Science, Coatings & Films
The gas sensing proper-ties of substoichiometric WO3 films have been i
nvestigated when activated with some gold monolayers sputtered on thei
r surface and in the as-deposited form. These films were deposited on
silicon substrates, in two steps: (i) chemical vapor deposition of tun
gsten films using W(CO)(6) vapors in a horizontal cold wall reactor at
a pressure of 13.3 Pa and temperatures between 773 and 823 K, and (ii
) oxidation of the tungsten films in air at 873 K for 10 min. For the
tests, the substoichiometric WO3 films were packed in classic dual in-
line packages. The resistance variations of these configurations cause
d by changes in their environment were monitored. Reversible changes,
of the order of several kilohms, were observed in th presence, or upon
removal H-2, at concentrations down 100 ppm, the magnitude of which d
epended on the concentration and the temperature measured. The respons
e times measured were also dependent on temperature and H-2 concentrat
ion, and were of the order of some minutes.