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 setup of a sensor suitable for indoor CO monitoring. The modification based on Au-clusters on the Ga₂O₃ surface yields high sensitivity towards CO and a distinct reduction of the cross sensitivity towards organic solvents. With the specimens, a resistance change of about a factor of 4 to 100 ppm CO in wet air is attained. By employing catalytic filters of ceramic material, cross sensitivities to organic solvents are nearly complete eliminated