Determination of the STM tip-graphene repulsive forces by comparative STM and AFM measurements on suspended graphene

András Pálinkás, György Molnár, Chanyong Hwang, László Péter Biró, Zoltán Osváth
  • RSC Advances, January 2016, Royal Society of Chemistry
  • DOI: 10.1039/c6ra19660h

STM tip-sample repulsive forces determined by scanning probe measurements on graphene nanobubbles

What is it about?

Graphene nanobubbles formed on gold nanoislands were investigated by scanning tunneling microscopy (STM) and atomic force microscopy (AFM). The nanobubbles could be squeezed both by AFM, using forces of 25-35 nN, and by STM, using bias voltages of less than 0.2 V. We concluded that at low bias voltages repulsive forces of the same order of magnitude (10 nN) are present during STM measurements as well. This finding agrees well with former results existing in the literature.

Why is it important?

The existance of mechanical forces during STM measurements can have important effects. For example, the tip can push away the investigated nanostructures when using low bias voltages.

Perspectives

Dr. Zoltán Osváth
MTA Centre for Energy Research (EK), Institute of Technical Physics and Materials Science (MFA)

Taking into consideration the observed effects, we are able to measure low-conducting nanoparticles by STM. We use high bias voltages in order to minimize repulsive tip-sample forces.

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http://dx.doi.org/10.1039/c6ra19660h

The following have contributed to this page: Dr. Zoltán Osváth