Direct visualization of local deformations in suspended few-layer graphene membranes by coupled in situ atomic force and scanning electron microscopy

Stefan Hummel, Kenan Elibol, Dengsong Zhang, Krishna Sampathkumar, Otakar Frank, Dominik Eder, Christian Schwalb, Jani Kotakoski, Jannik C. Meyer, Bernhard C. Bayer

Suspended membranes of two-dimensional (2D) materials are of interest for many applications. Much of their characterization relies on scanning probe microscopy (SPM) techniques such as atomic force microscopy (AFM) or scanning tunneling microscopy (STM). Unlike rigid samples, the suspended atomically thin 2D membranes are, however, flexible and do not remain mechanically undisturbed during SPM measurements. Local deformations can occur at the location of the scanning tip and thus result in measurements that misrepresent actual membrane topography and nanomechanical properties. Exact levels of such SPM tip-induced deformations in 2D membranes remain largely unknown, as they are to date only indirectly accessible via dual probe microscope concepts that either are not mechanically independent (e.g., SPM-SPM setups resulting in complicated imaging crosstalk) or suffer from intrinsically limited lateral resolution (e.g., optical far-field techniques as the second probe). Circumventing these shortcomings, we here demonstrate that by coupling an AFM with a scanning electron microscope (SEM) as the second, mechanically independent probe, we can directly and in situ visualize by SEM at high resolution 2D membrane deformations that result from controllable AFM tip manipulations in the nN range. Employing few-layer graphene as model membranes, we discuss the experimental realization of our coupled in situ AFM-SEM approach.

Physics of Nanostructured Materials
External organisation(s)
GETec Microscopy GmbH, Czech Academy of Sciences, Technische Universität Wien, Eberhard Karls Universität Tübingen, Brno University of Technology, Universität Wien, Shanghai University
Applied Physics Letters
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103042 Electron microscopy, 103018 Materials physics
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