Fabrication and characterization of nanocrystalline cobalt oxide thin films

A simple solution growth route has been employed to synthesize nanocrystall ine cobalt oxide thin films on glass substrates, The obtained films were ch aracterized by X-ray diffraction and FTIR spectroscopy. The as-deposited fi lms were identified as a mixture of different phases of Co(OH)(2), while th e annealed ones as Co3O4. The absorption of the annealed films gradually de creases with an increase of the wavelength in the 310-820 nm region, Upon a nnealing, the absorption coefficient decreases. The calculated band gap ene rgy from optical absorption data for annealed films is 2.2 eV. The as-depos ited thin films are dielectric, while the post-deposition heat-treated ones are characterized by resistivity of several M Omegas/cm(2) at room tempera ture. (C) 2001 Elsevier Science Ltd. All rights reserved.