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Enhanced conductance fluctuation by quantum confinement effect in graphene nanoribbons
Guangyu Xu1, Carlos M Torres, Emil B Song
1Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095, United States. guangyu@ee.ucla.edu
Nano Letters
|October 14, 2010
Summary
Conductance fluctuations in graphene nanoribbons (GNR) correlate with their electronic states. Noise measurements reveal a new way to electrically probe GNR band structures, even when conductance is unclear.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Conductance fluctuations are inherent in graphene nanoribbons (GNR) due to edge disorder.
- Understanding these fluctuations is key to characterizing GNR electronic properties.
Purpose of the Study:
- To investigate the relationship between conductance fluctuations and the electronic density-of-states in GNR.
- To establish a novel electrical method for probing GNR band structures.
Main Methods:
- Low-frequency noise measurements were performed on GNR devices.
- Analysis focused on the correlation between noise magnitude and the density-of-states.
- Gate-dependence of noise was studied to identify subband positions.
Main Results:
- A strong correlation was observed between conductance fluctuation and the density-of-states in GNR.
- Noise measurements in single-layer GNR exhibited gate-dependent peaks.
- The positions of these noise peaks precisely matched the predicted subband positions in GNR band structures.
Conclusions:
- Low-frequency noise is a sensitive probe of the electronic density-of-states in GNR.
- This noise-based method offers a robust way to electrically map GNR band structures.
- It is particularly effective when traditional conductance measurements are obscured by broadened subband structures.
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