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The conditions and physical mechanisms of electroforming and subsequent resistive switching in Au/TiO2/Pt thin film structures were investigated. It was concluded that the electroforming, being a current-limited electric breakdown of the TiO2 films, resulted in a considerable increase of the oxygen vacancy concentration in the bulk and on the surface of the films. The resistive switching implemented by short voltage pulses of different polarities is proposed to be due to the change of the Schottky barrier height at the Pt/TiO2 interface as a result of the current-induced variation of the occupancy by electrons of the surface states in the band gap of TiO2.

An impedance analysis of Ni/Pb(Zr,Ti)O3/Pt thin-film structures based on measurements at the frequencies from 100 Hz to 100 MHz, along with the data of Grazing Angles XRD, TEM and photo-electric study, is used to obtain electronic structure of the PZT thin films deposited by sol-gel method on silicone substrates. Both slow capacitance relaxation and charging/discharging currents versus time under step-voltage excitation have been studied in (Ba,Sr)TiO3 thin films between SrRuO3 electrodes.

Photoelectric phenomena were investigated in sol-gel derived lead zirconate-titanate (PZT) films. Two major illumination techniques were employed in order to assess both the ferroelectric polarization and internal field in the films. Using semitransparent top electrodes and short UV pulses, the fast polarization-dependent photocurrent was observed and attributed to bulk photovoltaic effect. This current can be used for non-destructive readout of polarization state in non-volatile ferroelectric memories. In the other regime, opaque electrodes were employed and a steady-state current (or voltage in the open circuit conditions) was investigated caused by the illumination of the area adjacent to the top electrode This polarization-independent current was ascribed to the internal field due to oxygen-deficient layer near the film's surface. It is shown that the observed photocurrent is sensitive to the wavelength of the light and can be used for the evaluation of electron band bending and electrical in...

Effect of the speed of bias voltage variation v on the dielectric non-linearity of metal-PZT-metal thin film capacitors has been studied. A distance ΔV between two maxima of C-V dependence on the voltage scale, characteristic for ferroelectric phase, as a function of the v value was investigated. It was established that decreasing vvalue led to ΔV decrease: ΔV = 1.8–2.0 V when v = 1.6x104 V/s, and ΔV ≅ 1.0 V when v = 6.5x10−2 V/s. The ΔV(v) dependence can be explained by the decreasing of the coercive field of the film due to the migration of charged mobile defects such as the doubly ionized oxygen vacancies, and the formation of space charge regions near the electrodes. Using the experimental data some parameters of the migration process were evaluated: the concentration of oxygen vacancies and their mobility were found to be about 1024 m−3 and 10−11 m2/Vs, respectively. These values are close to the data published in the literature obtained using the alternative methods of investigation.