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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Current saturation in zero-bandgap, top-gated graphene field-effect transistors
Inanc Meric1, Melinda Y Han, Andrea F Young
1Department of Electrical Engineering, Columbia University, New York 10027, USA.
Nature Nanotechnology
|November 8, 2008
Summary
Graphene field-effect transistors show transistor saturation for the first time. This breakthrough enables graphene
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Graphene's unique electronic properties, including its linear energy dispersion and 2D structure, drive research for nanoscale devices.
- Previous research has explored graphene's potential, but device-level characteristics like transistor saturation were not yet demonstrated.
Purpose of the Study:
- To report the first observation of saturating transistor characteristics in a graphene field-effect transistor (GFET).
- To investigate the factors influencing saturation velocity and current-voltage characteristics in GFETs.
- To assess the suitability of graphene for analogue and radio-frequency (RF) circuits.
Main Methods:
- Fabrication and characterization of graphene field-effect transistors.
- Measurement of current-voltage (I-V) characteristics and transconductance.
- Analysis using a field-effect model incorporating diffusive carrier transport and scattering mechanisms.
Main Results:
- First observation of saturating transistor characteristics in a GFET.
- Saturation velocity found to be dependent on charge-carrier concentration, attributed to interfacial phonon scattering.
- Unusual I-V features explained by a field-effect model and diffusive transport.
- High transconductances (up to 150 microS microm-1) achieved via efficient top-gate coupling, despite low on-off ratios.
Conclusions:
- Demonstrates the feasibility of graphene-based devices for analogue and RF applications.
- Transistor saturation in graphene is achievable without requiring bandgap engineering.
- Interfacial phonon scattering plays a key role in limiting carrier velocity.
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