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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Scanning gate microscopy on graphene: charge inhomogeneity and extrinsic doping
Romaneh Jalilian1, Luis A Jauregui, Gabriel Lopez
1Department of Physics, Purdue University, West Lafayette, IN 47907, USA.
Nanotechnology
|June 17, 2011
Summary
Scanning gate microscopy revealed mesoscopic domains in graphene field-effect transistors (GFETs). These GFETs exhibit significant spatial carrier density fluctuations due to local doping effects.
Area of Science:
- Condensed matter physics
- Materials science
- Nanotechnology
Background:
- Graphene field-effect transistors (GFETs) are crucial for next-generation electronics.
- Understanding carrier behavior in graphene is essential for device optimization.
- Spatial variations in graphene's electrical properties can impact device performance.
Purpose of the Study:
- To investigate the spatial distribution of carrier density in graphene.
- To explore the influence of local doping on graphene's electrical transport.
- To demonstrate graphene's sensitivity to local electric fields.
Main Methods:
- Scanning Gate Microscopy (SGM) was employed using a metallic nanowire tip.
- Electrical transport measurements were performed on GFETs.
- Back gate voltage, tip voltage, and tip position were systematically varied.
Main Results:
- Mesoscopic domains of electron-doped and hole-doped regions were observed near the Dirac point.
- Significant spatial fluctuations in carrier density were detected.
- Graphene resistance showed position-dependent variations in response to tip voltage.
Conclusions:
- Extrinsic local doping sources (e.g., contacts, defects) cause substantial carrier density fluctuations in graphene.
- GFETs exhibit excellent sensitivity to local electric fields and charges.
- SGM is a powerful technique for probing nanoscale electronic properties in graphene.
