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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Gate-voltage control of oxygen diffusion on graphene.
Alejandro M Suarez1, Ljubisa R Radovic, Ezra Bar-Ziv
1Department of Physics, Penn State University, University Park, Pennsylvania 16802, USA.
Physical Review Letters
|May 13, 2011
Summary
Gate voltage control significantly alters oxygen diffusion on graphene. Electron doping dramatically lowers the diffusion barrier, enabling control over oxidation patterns.
Area of Science:
- Materials Science
- Surface Science
- Physical Chemistry
Background:
- Graphene's unique electronic properties make it a promising material for various applications.
- Understanding atom diffusion on graphene surfaces is crucial for controlling material functionalization.
- Gate voltage modulation offers a tunable method to influence surface processes.
Purpose of the Study:
- To investigate the diffusion of oxygen atoms on graphene.
- To determine the influence of carrier density, controlled by gate voltage, on oxygen diffusion barriers.
- To explore the potential for gate-controlled patterning of oxidized regions on graphene.
Main Methods:
- Density Functional Theory (DFT) calculations were employed.
- Equilibrium adsorption sites and transition states for oxygen on graphene were determined.
- Attempt frequencies and diffusion barriers were calculated for varying carrier densities.
Main Results:
- Oxygen diffusion on graphene is highly sensitive to carrier density.
- A diffusion barrier of 0.73 eV was calculated for neutral graphene.
- Electron doping reduced the diffusion barrier to 0.15 eV at -7.6×10^13 cm^-2, increasing diffusion by over 9 orders of magnitude.
- Changes in bonding at equilibrium and transition states explain the observed diffusion behavior.
Conclusions:
- Carrier density modulation via gate voltage provides an effective means to control oxygen diffusion on graphene.
- The significant enhancement in diffusion with electron doping opens possibilities for precise patterning of graphene oxidation.
- This work highlights a novel approach for tailoring graphene surface chemistry using electrical stimuli.
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