Trap characterization for Bi4Ti3O12 thin films by thermally stimulated currents

Abstract.

Thermally stimulated current (TSC) measurements performed in the 100 K–400 K temperature range on Bi₄Ti₃O₁₂ (BiT) thin films annealed at 550 °C and 700 °C had revealed two trapping levels having activation energies of 0.55 eV and 0.6 eV. The total trap concentration was estimated at 10¹⁵ cm⁻³ for the samples annealed at 550 °C and 3×10¹⁵ cm⁻³ for a 700 °C annealing and the trap capture cross-section was estimated about 10⁻¹⁸ cm². From the temperature dependence of the dark current in the temperature range 20 °C–120 °C the conduction mechanism activation energy was found to be about 0.956–0.978 eV. The electrical conductivity depends not only on the sample annealing temperature but also whether the measurement is performed in vacuum or air. The results on the dark conductivity are discussed considering the influence of oxygen atoms and oxygen vacancies.