Preparation and characterization of metalorganic chemical vapor deposited nickel oxide and lithium nickel oxide thin films M. A. Eleruja G. O. Egharevba O. A. Abulude O. O. Akinwunmi C. Jeynes E. O. B. Ajayi Received: 24 May 2005 / Accepted: 22 February 2006 / Published online: 12 January 2007 Ó Springer Science+Business Media, LLC 2007 Abstract Thin films of nickel oxide and lithium nickel oxide were deposited through the pyrolysis of nickel acetylacetonate and lithium nickel acetylacetonate, respectively in the temperature range 350–420 °C. The single solid source precursors, nickel acetylaceto- nate and lithium nickel acetylacetonate were prepared and characterized using Energy Dispersive X-Ray Fluorescence (EDXRF), X-Ray Diffraction (XRD) and infrared spectroscopy. The composition, optical and electrical properties of the prepared thin films were analysed using a variety of techniques, including, Rutherford Backscattering Spectroscopy (RBS), EDXRF, XRD, UV–Visible Spectrophotometry and van der Pauw conductivity method. The amount of metals in the prepared thin films did not reflect the ratio of the metals in the precursor but was found to depend on the deposition temperature. The energy gaps of the nickel oxide and lithium nickel oxide thin films are 3.7 and 3.2 eV, respectively. The electrical conductivity showed that lithium nickel oxide thin film has an activation energy of 0.11 eV. The conduction was explained by a hopping mechanism. Introduction Transition metal oxides have generated renewed interest among research groups since the discovery of high temperature superconductors and the various interesting properties of this class of materials. More recently there has been a search for a completely inorganic electrochromic device for optical transmis- sion modulation. Inorganic transparent electrodes in the form of transition metal oxide thin films are used as electrochromic displays (ECD’s) in preference to polymers [1]. Nickel oxides, important members of this group, have been widely used for electrochromic anodes for the last decades [1]. Various deposition techniques have been used to deposit electrochromic nickel oxide and nickel-oxide-based thin films on different substrates. These include sol–gel-dip-coating technique [2], evaporation [3], RF sputtering [4], Pulsed Laser Deposition (PLD) [5] and MetalOrganic Chemical Vapour Deposition (MOCVD) [6]. A good number of properties of nickel-oxide-based thin films such as thermal [2] and structural analyses [7, 8] have been investigated. The search for alternate energy sources has shifted attention to a sub-group of transition metal oxides, such as Mo–O [9], Li–Ni–O, Li–Co–O [10], Li–Mo–O [11], among others. The interesting properties of such mate- rials have made them attractive for use as electrode materials in fuel cells [10, 11] and batteries for high M. A. Eleruja  O. A. Abulude  O. O. Akinwunmi  E. O. B. Ajayi (&)