Nanocrystalline ZnO thin films: optoelectronic and gas sensing properties

Nanocrystalline Zinc oxide thin films have been deposited by sol–gel spin coating technique and then have been analyzed before and after a suitable thermal annealing in order to test their applications in various reducing and oxidizing gases. ZnO thin films were highly sensitive and selective for NH₃ gas. The spectrophotometric and conductivity measurements have been performed in order to determine the optical and electrical properties of zinc oxide thin films. The structure and the morphology of such material have been investigated by high resolution electron microscopy and small area electron diffraction. The average particle size is in 60–70 nm.