A study of the sensitivity of ZnO-based sensors to CO, H-2, NH3, PH3, and AsH3

The dependences of the sensor conductivity on the temperature and gas concentrations have been obtained from studies of the conductivity of a sensor based on a polycrystalline ZnO film in air mixtures with CO, H-2, NH3, PH3, and AsH3. The results are discussed on the basis of a theoretical model considering the potential barrier between the grains of the polycrystalline film. Equations relating the sensor sensitivity (the relative change of its conductivity) to the change of the potential barrier in response to chemisorption have been derived.