CO Sensing Properties of Hetero-layered ZnO/SnO₂ Thin Films Prepared by the Sol-gel Method

Abstract

A hetero-layered ZnO/SnO₂ thin film was prepared by the sol-gel method to improve the sensing properties for the CO gas. The CO sensitivity and selectivity of the hetero-layered ZnO/SnO₂ thin film were both drastically improved than that of the single-layered Pd-SnO₂ thin film at a high operating temperature range from 300°C to 500°C. It was considered that the columnar ZnO layer deposited onto the SnO₂ layer was very effective in decreasing the influence of the interference gases, such as NO_x.