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arXiv · 0709.1174

Electrochemically Top Gated Graphene: Monitoring Dopants by Raman Scattering

A. Das·S. Pisana·S. Piscanec·B. Chakraborty·S. K. Saha·U. V. Waghmare·R. Yiang·H. R. Krishnamurhthy·A. K. Geim·A. C. Ferrari·A. K. Sood
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Abstract

We demonstrate electrochemical top gating of graphene by using a solid polymer electrolyte. This allows to reach much higher electron and hole doping than standard back gating. In-situ Raman measurements monitor the doping. The G peak stiffens and sharpens for both electron and hole doping, while the 2D peak shows a different response to holes and electrons. Its position increases for hole doping, while it softens for high electron doping. The variation of G peak position is a signature of the non-adiabatic Kohn anomaly at $Γ$. On the other hand, for visible excitation, the variation of the 2D peak position is ruled by charge transfer. The intensity ratio of G and 2D peaks shows a strong dependence on doping, making it a sensitive parameter to monitor charges.

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A. Das, S. Pisana, S. Piscanec, B. Chakraborty, S. K. Saha, U. V. Waghmare, R. Yiang, H. R. Krishnamurhthy, A. K. Geim, A. C. Ferrari, A. K. Sood. 2007-09-08. Electrochemically Top Gated Graphene: Monitoring Dopants by Raman Scattering. https://doi.org/10.1038/nnano.2008.67

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