PHYSICAL AND STRUCTURAL CHARACTERIZATION OF TUNGSTEN-OXIDE THIN-FILMSFOR NO GAS-DETECTION

Tungsten trioxide (WO,) thin films were rf sputtered from a WO, target in various oxygen/argon (O-2/Ar) atmospheres and at different total p ressures. A detailed structural and morphological investigation has be en carried out on all obtained films by high resolution electron micro scopy and nanodiffraction methods. Optical and electrical properties h ave been studied as function of deposition parameters. In addition, al l obtained films were tested in controlled atmosphere in order to inve stigate their response to NO in the interval 2-100 ppm in dry air. The sputtering parameters were optimized in order to obtain the maximum s ensitivity to NO gas. Finally, a close dependence between sputtering c onditions, morphological features and physical properties was observed . (C) 1998 Elsevier Science S.A. All rights reserved.