Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Graphene: Electronic Properties, Structure and Substrate Interaction

O 44.6: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Lifting Graphene from Substrates by Scanning Tunneling Microscopy — •Anne Holtsch, Anne Holtsch, Wolf-Rüdiger Hannes, and Uwe Hartmann — Universität des Saarlandes, Saarbrücken

Graphene as a two-dimensional crystal is only stable because of the formation of so-called ripples. Such ripples are thus called intrinsic and have been identified both by transmission electron microscopy [1] and scanning tunneling microscopy (STM) [2].

Here we study graphene grown via CVD and transferred onto copper foils, which may cause corrugations either before, during or after transfer. We find, however, that the corrugations appear very similar to those of free-standing membranes [2]. We report on the lifting of the graphene from the copper substrates using the attractive forces of a STM tip as previously reported for graphene on silicon dioxide [3].

Since metallic substrates electronically bind to the adsorbing graphene, higher bias voltages for lifting are generally required than in the case of free-standing membranes. Other features of Z(V) spectroscopy curves such as reversible flipping processes with hysteric behavior are also analyzed. It is discussed wether interaction strengths between graphene and particular types of substrates can be deduced from such measurement.

[1] J. C. Meyer et al., Nature 446, 60 (2007) [2] R. Dan et al., Nanoscale 4, 3065 (2010) [3] T. Mashoff et al., Nano Lett. 10, 461 (2010)