Publication Date:
2014-08-28
Description:
Despite the noble electronic properties of graphene, its industrial application has been hindered mainly by the absence of a stable means of producing a band gap at the Dirac point (DP). We report a new route to open a band gap (E g ) at DP in a controlled way by depositing positively charged Na + ions on single layer graphene formed on 6H-SiC(0001) surface. The doping of low energy Na + ions is found to deplete the π * band of graphene above the DP, and simultaneously shift the DP downward away from Fermi energy indicating the opening of E g . The band gap increases with increasing Na + coverage with a maximum E g ≥ 0.70 eV . Our core-level data, C 1 s , Na 2 p , and Si 2 p , consistently suggest that Na + ions do not intercalate through graphene, but produce a significant charge asymmetry among the carbon atoms of graphene to cause the opening of a band gap. We thus provide a reliable way of producing and tuning the band gap of graphene by using Na + ions, which may play a vital role in utilizing graphene in future nano-electronic devices.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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