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Analysis of Contact Interfaces for Single GaN Nanowire Devices
Published on: November 15, 2013
Understanding anomalous current-voltage characteristics in microchannel-nanochannel interconnect devices
Vishal V R Nandigana1, N R Aluru
1Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Journal of Colloid and Interface Science
|July 20, 2012
Summary
This study explains anomalous current-voltage behavior in nanochannels using numerical simulations. Overlimiting currents arise from space charge redistribution, enhancing ion concentration and conductivity.
Area of Science:
- Electrokinetics
- Nanofluidics
- Ion Transport
Background:
- Microchannel-nanochannel integration exhibits nonlinear current-voltage (I-V) characteristics.
- Highly ion-selective nanochannels show limiting resistance and overlimiting current regions.
Purpose of the Study:
- To numerically simulate and explain the physics behind anomalous nonlinear I-V characteristics in nanochannels.
- To investigate the origins of overlimiting current and anomalous rectification effects.
Main Methods:
- Detailed 2-D numerical simulations of nonlinear ion transport.
- Analysis of space charge redistribution and ionic concentration enhancement.
- Investigation of combined AC and DC electric field effects.
Main Results:
- Overlimiting current attributed to space charge redistribution and enhanced ionic concentration beyond critical voltage.
- Constant conductivity predicted for overlimiting current, independent of fluidic nonlinearities.
- Anomalous rectification effects observed with combined AC/DC fields, enhancing current in non-ohmic regions.
Conclusions:
- Space charge redistribution is the primary mechanism for overlimiting currents in nanochannels.
- Anomalous rectification can be achieved in nanochannels using combined AC/DC fields.
- The study provides criteria and scaling relations for observing these phenomena.
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