Elaboration and characterization of Co doped, conductive ZnO thin films deposited by radio-frequency magnetron sputtering at room temperature

Nanocrystalline, highly (at.%) Co doped ZnO powder, obtained by a modified sol-gel method, was used as a target material for the growth of pm thin films by radio frequency magnetron sputtering. The films were deposited at room temperature on quartz substrates. The as-deposited films were polycrystalline but highly textured with the c-axis aligned normal to the substrate plane. They present high optical transmittance in the visible range of approximately 90%, a carrier concentration of about 10(20) cm(-3) and electrical resistivity of 10(-3) Omega cm at room temperature. The analysis of the Co2+ spectrum by electron paramagnetic resonance (EPR) showed the Co to be incorporated substitutionally and the angular variation EPR spectrum demonstrates a monocrystal like texturing of the films with the c-axis normal to the film plane. (C) 2009 Elsevier B.V. All rights reserved.