Detection mechanism of metal oxide gas sensor under UV radiation

The effect of ultraviolet radiation on the sensing mechanism of polycrystalline metal oxide gas sensor has been studied analytically. The model used to describe the sensing mechanism is based on the combination of the neck mechanism and grain boundary mechanism. We found that increasing the UV radiation flux density increases the conductivity of the film by decreasing the resistance. It has been shown theoretically that due to incident UV radiation, it is possible to detect the gas even at room temperature. The effect of radiation on the sensitivity is discussed as a function of grain size and chemisorbed gas concentration. (C) 2003 Elsevier B.V. All rights reserved.