CO-sensor for domestic use based on high temperature stable Ga2O3 thin films

Gas sensors based on high temperature operated metal oxides, like Ga2O3 thin films show promising properties in terms of reproducibility, long-term stability against interfering gases and low cross sensitivity to humidity. In this paper a surface modification of Ga2O3 is presented which allows the set up of a sensor suitable for indoor CO monitoring. The modification based on Au-clusters on the Ga2O3 surface yields high sensitivity to CO and a distinct reduction of the cross sensitivity towards organic solvents. With the specimens, a resistance change of approx. factor 4 to 100 ppm CO in wet air is attained. By employing catalytic filters of ceramic material, cross sensitivities to organic solvents are virtually completely eliminated. (C) 1998 Elsevier Science S.A. All rights reserved.