"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

NANOGRAIN WO3 THIN FILMS AS ACTIVE LAYER FOR RESISTIVE TYPE GAS SENSORS

M. Stankova1,* , X. Vilanova2, J. Calderer2, I. Gràcia3, C. Cané3, X. Correig1

Affiliation

  1. Department of Engineering Electronics, University Rovira i Virgili, Avda. Països Catalans 26, 43007 Tarragona, Spain
  2. Department of Engineering Electronics, Polytechnic University of Catalonia, Barcelona, Spain
  3. Department of Microsystems and Silicon Technologies, CNM, Bellaterra, Spain

Abstract

Pure and Pt doped WO3 thin films were studied as active layers for resistive type microhotplate gas sensors. The layer of WO3 was deposited by reactive rf magnetron sputtering on four element micromachined sensor array and was defined using lift-off method. The obtained film was doped with Pt employing the same deposition technique. An annealing process at 400 °C for 2 h in air was realized to ensure the film stability. The morphology of the layer was studied by SEM. Transmission electron microscopy was used to analyse the platinum thickness and distribution. The WO3 phase was determined by XRD. The obtained sensors were used to detect traces of pollutants in a carbon dioxide stream. The results showed that the sensors were capable to detect the sulphur compounds in the presence of hydrocarbons. The pure WO3 sensors were sensitive to very low concentrations of H2S (100 ppb), while the doped ones presented high response to 1 ppm of SO2. The influence of the operating temperature and the electrodes configuration was also studied..

Keywords

Thin film gas sensors, Rf sputtering, CO2 quality.

Submitted at: April 18, 2005
Accepted at: May 26, 2005

Citation

M. Stankova, X. Vilanova, J. Calderer, I. Gràcia, C. Cané, X. Correig, NANOGRAIN WO3 THIN FILMS AS ACTIVE LAYER FOR RESISTIVE TYPE GAS SENSORS, Journal of Optoelectronics and Advanced Materials Vol. 7, Iss. 3, pp. 1237-1242 (2005)