New gas sensing properties of high Tc cuprates

We have discovered an interesting property of high T-c cuprates, which are popularly known as high temperature superconductors, for gas sensing applications. Metallic films of YBCO and BSCCO compounds are examined for gas-sensing properties by incorporating them in a FET-sensor structure. These multi-component ceramic oxides exhibited room temperature gas detection capability in comparison to conventional metal-oxides, which are sensitive to gases only at elevated temperatures. The sensor responses to NH3, H-2, CO, CO2, NO, NO2, and hydrocarbon gases are presented and discussed. The results evince that thin film of high T-c cuprates are highly sensitive to NH3 and NO2 at and around room temperature and less sensitive to other gases. These films, therefore, can be used to realize a room temperature low power FET-gas sensor. (C) 1999 Elsevier Science S.A. All rights reserved.