Impact of top metal electrodes on current conduction in WO₃ thin films

Abstract

Using radio-frequency (rf) sputtering technique tungsten oxide (WO3) thin films (∼150 nm) were deposited in a gas mixture of Ar and O2 at 10 mTorr pressure on indium tin oxide (ITO) and corning glass substrates. The films were annealed at 400 °C. Structural and optical properties of films were studied. Metal–insulator–metal (MIM) structure was made by depositing metal electrode (Ag, Al, Au) on the prepared WO3 thin films (on ITO substrate) using thermal evaporation technique. Electrical properties of the MIM structure were studied by plotting current versus voltage (I–V) curves for Ag, Al and Au metal electrodes. Current conduction mechanism in WO3 film was determined by plotting and fitting I–V data in different equations of current mechanisms.