Nonlinear electrical properties (poster3) · 2015. 7. 20. · Nonlinear electrical properties of...
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Nonlinear electrical properties of grain boundaries in BaZrO 3 M. Shirpour, C. T. Lin, R. Merkle, and J. Maier Max Planck Institute for Solid State Research, Stuttgart, Germany • Large Large grained grained sample sample: Infrared Image Furnace (~2600 °C) Feed rod Seed rod Molten Zone Crystal Quartz tube Ellipsoidal mirror Lamp • GB GB electrical electrical properties properties under under DC DC bias bias: • Microcontact Microcontact impedance impedance spectra spectra of of individual individual GBs GBs: Microcontact setup Microelectrodes and position of needles Impedance spectra within one grain / across one GB Schottky barrier with interface states Schottky barrier without interface states Thermionic emission Drift-diffusion Electron tunnelling Modelling on p-type SrTiO 3 decrease of R GB and C GB under DC bias supports space charge model Continuous GB secondary phase as reason for blocking GB: - could also lead to R GB decreasing with bias (BV-analogous increase of electron/proton hopping rate) - but constant C GB expected * R bulk ≈ constant (C bulk hidden by C stray ) * R GB decreases with applied bias * C GB decreases with applied bias capacitance of space charge zones: * model with interface states: core charge increases under bias → depletion zone broadens → C GB decreases already at moderate bias * model without interface states: large bias: imcomplete depletion on one side → depletion zone broadens → C GB ⇓ Holbling, Waser, J. Appl. Phys. 91 (2002) 3037 Emtage, J. Appl. Phys. 48 (1977) 4372 Riess, Maier, Phys. Rev. Lett. 100 (2009) 205901 Impedance spectra under DC bias: Voltage dependent GB resistance and capacitance: • Voltage dependent GB electrical properties explained by differen Voltage dependent GB electrical properties explained by different t models: models:
Transcript of Nonlinear electrical properties (poster3) · 2015. 7. 20. · Nonlinear electrical properties of...
Nonlinear electrical properties of grain boundaries in BaZrO3
M. Shirpour, C. T. Lin, R. Merkle, and J. Maier
Max Planck Institute for Solid State Research, Stuttgart, Germany
•• Large Large grainedgrained samplesample: Infrared Image Furnace (~2600 °C)
Feed rod
Seed rod
Molten Zone
Crystal
Quartz tube
Ellipsoidal mirror
Lamp
•• GB GB electricalelectrical propertiesproperties underunder DC DC biasbias::
•• MicrocontactMicrocontact impedanceimpedance spectraspectra of of individualindividual GBsGBs::
Microcontact setup Microelectrodes and position of needles
Impedance spectra within one grain / across one GB
Schottky barrier with interface states Schottky barrier without interface states
Thermionic emissionDrift-diffusionElectron tunnelling
Modelling on p-type SrTiO3
decrease of RGB and CGB underDC bias supports space charge model
Continuous GB secondary phase as reason for blocking GB:
- could also lead to RGB decreasing with bias(BV-analogous increase of electron/proton hopping rate)
- but constant CGB expected
* Rbulk ≈ constant (Cbulk hidden by Cstray)
* RGB decreases with applied bias
* CGB decreases with applied bias
capacitance of space charge zones:
* model with interface states:core charge increases under bias→ depletion zone broadens→ CGB decreases already at moderate bias
* model without interface states:large bias: imcomplete depletion on one side→ depletion zone broadens → CGB ⇓ Holbling, Waser,
J. Appl. Phys. 91 (2002) 3037
Emtage, J. Appl. Phys. 48 (1977) 4372
Riess, Maier, Phys. Rev. Lett. 100 (2009) 205901
Impedance spectra under DC bias: Voltage dependent GB resistance and capacitance:
•• Voltage dependent GB electrical properties explained by differenVoltage dependent GB electrical properties explained by different t models:models:
