Synthesis and characterization of SnO2-ZnO composite thin films deposited via spray pyrolysis
Composite films based from tin dioxide (SnO2) and zinc oxide (ZnO) was synthesized on a glass substrate via spray pyrolysis at a substrate temperature of 350°C. SnO2-ZnO composite films were obtained by varying the volumetric amount of zinc acetate precursor solution (25 vol%, 50 vol%, and 75 vol%). The results of scanning electron microscopy and X-ray diffraction analysis showed an increase in the grain size of the composite film as the ZnO volume ratio increased. UV-Vis spectroscopy revealed a decrease in the transmittance spectra of the composite films with zinc acetate volume concentrations of 50%, which is due to thicker film achieved at 50-50 combination of the films. The optical band gap energy was computed by extrapolating the straight line in the Tauc's plot to zero. The computed optical band gap has a decreasing trend as the ZnO volume ratio increases.