Characterization and gas sensing properties of copper-doped tin oxide thin films deposited by ultrasonic spray pyrolysis

Abstract

Tin oxide-based thin films are deposited by ultrasonic spray pyrolysis technology, in which Cu addition is introduced to enhance the gas sensing performance by H2S detection. The thin films are porous and comprise nano-sized crystallites. One of the Cu-containing thin film sensors demonstrates a fast and significant response to H2S gas. The values of power law exponent n are calculated to discuss the sensitivity of the sensors, which is significantly promoted by Cu additive. The sensitivity of Cu-doped SnO2 gas sensors is determined by two mechanisms. One is the normal gas sensing mechanism of SnO2 grains, and the other is the promoted mechanism caused by the transformation between CuO and CuS in the H2S detection.