Physical properties of nanocrystalline CuO thin films prepared by the SILAR method

We report a facile and low-cost successive ionic layer adsorption and reaction method to synthesize nanocrystalline CuO thin films. Influence of deposition cycles on the physical properties of nanocrystalline CuO thin films was investigated. X-ray diffraction studies show that all the films exhibit polycrystalline nature with monoclinic crystal structure. Fourier transform infrared spectroscopy and Raman studies confirmed the formation of single phase CuO wherein the characteristic vibrational mode of Cu-O was identified. Scanning electron microscopy studies revealed the formation of sporadic growth of rod-shaped elongated particles. Both the structural and surface properties of CuO thin films were improved with the increase in the deposition cycles as a result of which the optical absorption edge of CuO shift towards longer wavelength, and the optical band gap energy decreases from 2.48 eV to 2.31 eV. The room-temperature photoluminescence spectrum showed blue emission band centered at 468 nm, attributed to the near-band-edge emission of CuO due to Burstein-Moss effect. (C) 2012 Elsevier Ltd. All rights reserved.