The Effect of Deposition Parameters on the Sensing Behaviors of the SnO 2 : Cu Nano-structure Thin Films Including Co 2 -gas Sensor

Abstract

In this work, Cu-doped SnO 2 thin films were deposited by spray pyrolysis method. The films were prepared using SnCl 4 ,5H 2 O and CuCl 2 ,2H 2 O hydro-alcoholic solution. Then, the sensitivity parameter of SnO 2 -based CO 2 -gas sensors is studied for various atomic percentages ([Cu]/[Sn] = 0, 2, 4, 6, 10,12.5,15, 20, 25). In addition, the effect of substrate temperature on the sensing behavior of films was also studied. The XRD and SEM structural analysis of thin film sensors confirm the nano-structure of the films with SnO 2 cassiterite phase. The optical band gap of Cu doped- SnO 2 films were obtained from optical absorption spectra by UV-Vis absorption spectroscopy. Measurement of the electrical resistivity of films shows that with increasing of Cu-doping in films up to 12.5%, the electrical resistivity increase sharply.