Gas detection sensitivity and cluster size

A theoretical investigation of the dependence of gas sensitivity of nanostr uctured semiconductor gas sensors on cluster size is presented The clusters are represented as spheres and the adsorbed gas as a surface stare density . The sensitivity is calculated as a change in conductivity over a change o f surface state density. The results show that there is a critical cluster size, which is material dependent, at which the sensitivity is maximal. The cluster size for maximum sensitivity of several metal oxide gas sensors of practical interest, such as ZnO, SnO2, TiO2 and In2O3, is predicted and di scussed. (C)1999 Acta Metallurgica Inc.