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Published on: July 24, 2015
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Large-area high-quality graphene on Ge(001)/Si(001) substrates
I Pasternak1, P Dabrowski, P Ciepielewski
1Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw, Poland. Iwona.pasternak@itme.edu.pl.
Nanoscale
|May 19, 2016
Summary
High-quality graphene films were successfully grown over large areas on germanium-on-silicon substrates using chemical vapor deposition. This advancement offers a uniform, well-oriented graphene monolayer with excellent electronic properties for advanced applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Large-area, high-quality graphene synthesis is crucial for electronic applications.
- Chemical Vapor Deposition (CVD) is a primary method for graphene production.
- Germanium-on-Silicon (Ge(001)/Si(001)) substrates offer unique properties for epitaxial growth.
Purpose of the Study:
- To investigate the growth of large-area, high-quality graphene films on Ge(001)/Si(001) substrates via CVD.
- To characterize the structural, electronic, and orientational properties of the synthesized graphene.
- To assess the homogeneity and quality of the graphene layer for potential applications.
Main Methods:
- Scanning Electron Microscopy (SEM) for surface morphology.
- Scanning Tunneling Microscopy (STM) for nano-facet analysis and atomically resolved imaging.
- Raman Spectroscopy for monolayer confirmation, strain, and charge fluctuation analysis.
- Scanning Tunneling Spectroscopy/Current Imaging Tunneling Spectroscopy (STS/CITS) for terrace quality.
- Low Energy Electron Diffraction (LEED) for crystallographic orientation.
- Low Temperature Hall Measurements for carrier concentration and mobility.
Main Results:
- Uniform graphene monolayer formation across nano-faceted Ge(001) surfaces (1 cm²).
- Nano-facets exhibit hill-and-valley structures along <100> directions with ~10 nm height difference.
- Raman spectroscopy indicates minimal strain and charge fluctuations.
- STM/STS/CITS confirm high-quality graphene on terraces.
- LEED reveals two preferred orientations for the large-area graphene layer.
- Hall measurements show n-type concentration (9.3 × 10¹² cm⁻²) and high mobility (2500 cm²/V·s).
Conclusions:
- CVD growth on Ge(001)/Si(001) yields large-area, high-quality graphene monolayers.
- The nano-faceted surface promotes uniform graphene coverage and domain coalescence.
- The obtained graphene exhibits excellent electronic properties and high homogeneity.
- This method is promising for scalable production of graphene for electronic devices.
