nonlinear electrical properties (poster3) · 2015. 7. 20. · nonlinear electrical properties of...
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![Page 1: Nonlinear electrical properties (poster3) · 2015. 7. 20. · Nonlinear electrical properties of grain boundaries in BaZrO3 M. Shirpour, C. T. Lin, R. Merkle, and J. Maier Max Planck](https://reader035.vdocuments.us/reader035/viewer/2022063016/5fd52365389a76096b030543/html5/thumbnails/1.jpg)
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: