Characterization of Metal Oxide Sensor Thin Films Deposited by Spray Pyrolysis

Chemical Spray Pyrolysis (CSP) of ZnO and SnO₂ is of interest for gas sensor applications. The structural properties of the deposited film can be strongly influenced by deposition conditions. In this work, two solutions consisting of Tin Chloride and Zinc Chloride was sprayed on a heated substrate, where temperature was varied from 400° C to 450° C for ZnO, and from 350° C to 500° C for SnO₂. X-ray diffraction and scanning electron microscopy, indicating a non-homogenous-structured film formed at low temperature for both oxides. At 450° C, a porous structure is observed for SnO2. This structure becomes homogenous at higher temperature. It was also found that at temperatures lower than 450° C, substrate temperature has significant impact on the composition of the synthesized films.