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Partial hydrogenation induced interaction in a graphene-SiO2 interface: irreversible modulation of device
Takuya Iwasaki1, Manoharan Muruganathan1, Marek E Schmidt1
1School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan. t.iwasaki@jaist.ac.jp mano@jaist.ac.jp.
Nanoscale
|January 12, 2017
Summary
Vacuum annealing enhances graphene conductivity by reducing impurities and inducing n-type doping. Hydrogen annealing, however, degrades conductivity irreversibly due to surface interactions, impacting graphene devices.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Surface Science
Background:
- Graphene's electronic properties are sensitive to surface interactions and doping.
- Annealing is a common method to modify graphene's characteristics.
- Understanding annealing effects on graphene/SiO2 is crucial for device applications.
Purpose of the Study:
- To investigate and compare the effects of vacuum and hydrogen/argon annealing on graphene devices on SiO2.
- To elucidate the mechanisms behind the observed changes in graphene's electronic properties.
- To analyze the role of surface interactions and doping.
Main Methods:
- Experimental characterization of graphene devices.
- Van der Waals interaction corrected Density Functional Theory (DFT) simulations.
- Analysis of carrier mobility, conductivity, and surface chemistry.
Main Results:
- Vacuum annealing removes p-type dopants, reduces scattering, and induces n-type doping, improving electron mobility and conductivity.
- Hydrogen/argon annealing results in lower n-type doping, decreased conductivity and mobility, with irreversible degradation.
- DFT simulations revealed hydrogen passivation of silicon dangling bonds and reduced graphene-SiO2 distance, explaining conductivity loss.
Conclusions:
- Vacuum annealing offers a reversible method to enhance graphene's electron transport properties.
- Hydrogen annealing leads to irreversible degradation of graphene conductivity due to detrimental surface interactions.
- Both methods impact the graphene channel near metal contacts, influencing carrier transport asymmetry.
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