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Quantum Hall effect in a gate-controlled p-n junction of graphene
J R Williams1, L Dicarlo, C M Marcus
1School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138, USA.
Science (New York, N.Y.)
|June 30, 2007
Summary
Researchers created a graphene p-n junction using local electrostatic gating, enabling control over carrier type and density. This breakthrough paves the way for future graphene-based bipolar nanoelectronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanoelectronics
Background:
- Graphene's unique electronic band structure facilitates electric-field control of carrier properties.
- This tunability makes graphene a promising material for bipolar nanoelectronic applications.
Purpose of the Study:
- To realize a single-layer graphene p-n junction with locally controlled carrier type and density.
- To investigate the transport properties of this junction in the quantum Hall regime.
Main Methods:
- Fabrication of a single-layer graphene p-n junction using local electrostatic gating.
- Transport measurements in the quantum Hall regime.
Main Results:
- Demonstrated local electrostatic gating to control carrier type and density in adjacent graphene regions.
- Observed new plateaus of two-terminal conductance at 1 and 32 times the quantum of conductance (e²/h) across the junction.
- Results are consistent with theoretical predictions.
Conclusions:
- The local-gating technique provides a foundation for graphene-based bipolar technology.
- This work enables further condensed-matter physics investigations using graphene p-n junctions.
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