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DIELECTRIC PROPERTIES OF MOLYBDENUM OXIDE THIN FILMS

Esmat Abdel-Fattah I. Saad1,*

Affiliation

  1. Department of Engineering Physics and Mathematics, Faculty of Engineering, Ain Shams University, Cairo, Egypt

Abstract

AC coductivity measurements of Molybdenum Oxide thin films (MoO3) are investigated within the frequency range 102-2.5×105 Hz and the temperature range of 273 – 393 K. The frequency dependence of the impedance measurements plotted in the complex plane reveals three semicircular arcs. The system could be represented by an equivalent circuit of a bulk resistance in series with three parallel resistance-capacitance combinations corresponding to contributions from the grain-bulk, grain-boundary, and electrode–film regions. The dielectric constant increases with temperature and decreases with frequency, whereas the dielectric loss displays a broad maximum peak whose position shifts with temperature to a higher frequency region. The Cole – Cole diagrams of the relation ( ) show also three semicircular arcs, where some regions dominate the others. The temperature-dependence of, both the molecular relaxation time and dc conductivity , yield for the first time, three lines with different activation energies. The optical dielectric constant was also separated to three curves, which increase with temperature to give broad peaks at ~341K..

Keywords

Molybdenum oxide, Thin films, Dielectric properties, Relaxation time, Grain-bulk, Grain-boundary, Electrode–film, Impedanc measurements.

Submitted at: May 31, 2005
Accepted at: Sept. 22, 2005

Citation

Esmat Abdel-Fattah I. Saad, DIELECTRIC PROPERTIES OF MOLYBDENUM OXIDE THIN FILMS, Journal of Optoelectronics and Advanced Materials Vol. 7, Iss. 5, pp. 2743-2752 (2005)