Humidity response of SnO[sub 2] thin films deposited by spray pyrolysis

Abstract

Transparent SnO2 films, using precursor solutions of different molar concentrations (0.2, 0.4, 0.6 and 0.8M), are prepared by spray pyrolysis method. XRD spectra of the films reveal polycrystalline nature. Surface morphology presents jelly like structures as seen through scanning electron microscope. Humidity sensing behaviour has been studied considering resistance of the films as a monitor parameter. Sensitivity is seen to increase as relative humidity (RH) increases for all the samples. Sensitivity is highest for SnO2 film prepared with precursor of lowest molar concentration (0.2M). Response and recovery time, for the sample with highest sensitivity, are found to be 20 and 25 sec respectively.