Oxide-based resistive switching devices are promising candidates for new memory and computing technologies. Poor understanding of the defect-based mechanisms that give rise to resistive switching is a major impediment for engineering reliable and reproducible devices. Here we identify an unintentional interface layer as the origin of resistive switching in Pt/Nb:SrTiO3 junctions. We clarify the microscopic mechanisms by which the interface layer controls the resistive switching. We show that appropriate interface processing can eliminate this contribution. These findings are an important step towards engineering more reliable resistive switching devices.

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Resistive switching and its suppression in Pt/Nb:SrTiO3 junctions

Intrinsic electrical properties of Au/Nb-doped SrTiO3(001) (STO:Nb) Schottky junctions, fabricated using a proper surface treatment of the STO:Nb and in situ deposition of Au, were investigated in detail. Current–voltage characteristics and photocurrent–wavelength characteristics have shown a temperature-dependent and voltage-dependent Schottky barrier height, while capacitance–voltage characteristics have shown a temperature-independent flat band voltage. Using a temperature-dependent and field-dependent permittivity of the STO in the framework of Devonshire theory, we have performed computer simulation of the Schottky barrier potential to analyze the electrical properties of the junction. It is found that an intrinsic low permittivity layer at the Au/STO:Nb interface explains all the temperature dependence of the electrical properties.

Intrinsic electrical properties of Au/SrTiO3 Schottky junctions

A reproducible process for fabricating Ba1−xKxBiO3/Nb-doped SrTiO3 (BKBO/STNO) all-oxide-type Schottky junctions has been established, and the electrical properties of the junctions have been investigated at room temperature Improving the STNO surface conditions by high-temperature oxygen-annealing made it possible to fabricate junctions with good rectification properties The current–voltage characteristics of the junctions were explained by conventional thermionic emission theory Anomalous capacitance–voltage characteristics of the junctions were observed and were analyzed with a model taking into account the electric-field-dependent permittivity of STNO and the presence of the interfacial layer The potential barrier profile of the BKBO/STNO interface was calculated and it can be concluded that this model quantitatively explains the capacitance–voltage characteristics

Fabrication and characterization of Ba1−xKxBiO3/Nb-doped SrTiO3 all-oxide-type Schottky junctions

Photoelectrolysis of water by irradiation of platinized n-type semiconducting metal oxides☆

The leakage current density–applied field (J−EA) characteristics of (BaxSr1−x)Ti1+yO3+z (BSTO) thin film capacitors with Pt electrodes that have been annealed in forming gas (95% Ar 5% H2 or D2) were investigated over the temperature range from −60 to +60 °C. Forming gas annealing significantly increased the leakage current density. The J–EA characteristics exhibited features that could not be fully explained by either a simple thermionic emission or tunneling (Fowler–Nordeim) formalism. Using the general charge transport theory of Murphy and Good, we show that the J–EA characteristics can be successfully interpreted in terms of tunneling of electrons through the interfacial Schottky barrier with the peak in energy distribution of the incident carriers strongly dependent on applied field. At high applied fields the energy distribution of incident carriers is peaked near the Fermi level in the electron injecting metal electrode at all temperatures considered in this study, leading to almost temperature ind...

Hydrogen induced tunnel emission in Pt/(BaxSr1−x)Ti1+yO3+z/Pt thin film capacitors

Capacitance vs bias voltage data are presented for Au–KTaO3 surface barrier Schottky diodes. Substantial deviations from the normal Schottky capacitance relationship have been observed and attributed to a field‐dependent dielectric constant in the depletion layer. From the capacitance data obtained at room temperature, e vs E and P vs E curves have been calculated for KTaO3 and found to be consistent with previous measurements made using conventional techniques at 4.2°K.

S. H. Wemple

Papers

Measurement of Nonlinear Polarization of KTaO3 using Schottky Diodes