Zinc oxide based coatings are of much interest in science and technology due to their interesting applications, such as in gas sensor devices, transparent electrodes, piezoelectric devices, varistor ,surface acoustic-wave devices ,etc. Thin films of ZnO also have some advantages over indium tin oxide (ITO) and tin oxide, which are usually used as transparent conductors, the former are chemically stable to a hydrogen plasma such as that used in the elaboration of solar cells. Many techniques have been employed to produce zinc oxide based coatings e.g. radio frequency magnetron, spray pyrolysis, sputtering, chemical vapor deposition, sol gel, pulsed laser deposition, etc. Among these techniques, the spray pyrolysis has proved to be a simple, reproducible, and inexpensive method, particularly useful for large area applications.

The main features of the spray pyrolytic system are fully described elsewhere. We have used a spray system attached onto mobile stage that provides a sweeping movement to the spray nozzle.