The influence of microstructure and deposition methods on CO gas sensing properties of La0.8Sr0.2Co1-xNixO3-delta perovskite films

The sensing characteristics to CO of the La0.8Sr0.2Co1-xNixO3-delta perovsk ite sensor films were strongly dependent on the deposition methods. By the dipping method, the maximum sensitivity was obtained on the film treated at 800 degrees C for 30 min. By the RF sputtering method, only the heat treat ed film showed response to CO. The maximum sensitivity was obtained in the film treated at 700 degrees C for 5 h. The sensitivity variation was affect ed by their grain morphologies. It is found that more porous films exhibit a larger sensitivity. Comparing these two techniques, the film made by the dipping method showed both larger sensitivity and lower operating temperatu re (180 degrees C). This phenomenon can be attributed to the larger surface reaction area on sensitivity. In addition, different binding energy states of oxygen can also influence the sensing properties to CO. (C) 1999 Elsevi er Science S.A. All rights reserved.