Mn doped and undoped ZnO films: A comparative structural, optical and electrical properties study

Undoped and manganese doped zinc oxide (ZnO) thin films were prepared by pyrolytic decomposition of aqueous solution onto glass substrates. The structural properties studied using X-ray diffraction showed that the undoped ZnO films exhibit hexagonal wurtzite structure with strong c-axis orientation, however Mn doped ZnO films were polycrystalline. The surface morphological studies from SEM depicted the formation of clusters like structure of undoped ZnO while the Mn doped film showed the nanocrystalline grains on the surface. From the optical studies, the transmittance in the wavelength range 350-850 nm was found to be decreased after doping of Mn. The optical band gap was found to be 3.3eV for undoped ZnO film and 3.10eV for Mn doped films. From the electrical resistivity measurement, it is found that the Mn doping significantly caused to increase the room temperature resistivity from 10(4) to 10(6) Omega cm. (c) 2005 Elsevier B.V. All rights reserved.