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arXiv · 1008.3606

Tip induced doping effects in local tunnel spectra of graphene

Shyam K. Choudhury·Anjan K. Gupta
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Abstract

We report on tip induced doping in local tunnel spectra of single layer graphene (SLG) with tunable back-gate using room temperature scanning tunneling microscopy and spectroscopy (STM/S). The SLG samples, prepared on silicon dioxide surface by exfoliation method and verified by Raman spectra, show atomically resolved honeycomb lattice. Local tunnel spectra show two minima with a clear evolution in the position of both with doping by the back gate. A similar variation in spectra is also observed spatially due to charge inhomogeneity. With doping the two minima move in opposite directions with one showing nearly a square root dependence and the other a linear dependence on gate voltage. We explain these features as arising from the STM tip induced and bias voltage dependent doping in SLG.

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Shyam K. Choudhury, Anjan K. Gupta. 2010-08-21. Tip induced doping effects in local tunnel spectra of graphene. https://doi.org/10.1063/1.3555344

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