Bilkent researchers’ AFM/STM asymmetry work on graphene has been highlighted on the cover of the Journal of Vacuum Science & Technology B.
Graphene—a two-dimensional sheet of carbon atoms arranged in a honeycomb pattern—has received tremendous attention from the scientific community in the last decade due to its outstanding physical properties. The discovery of this “wonder material” in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester brought them a Nobel Prize in Physics.
Now, researchers in the Scanning Probe Microscopy (SPM) Research Group led by Asst. Prof. Mehmet Z. Baykara of the Department of Mechanical Engineering have contributed to the atomic-scale understanding of this material, as documented in an article featured on the cover of the May 2015 issue of the Journal of Vacuum Science & Technology B.
Asked about the motivation for the work, Dr. Baykara said, “Graphene has exceptional potential for practical applications, but integrating it into functional devices requires a comprehensive understanding of its atomic-scale properties. Toward this goal, scanning probe microscopy has been utilized since the discovery of the material. However, experiments conducted by different research groups around the world have often led to conflicting results.”
Thanks to the research discussed in detail in the article, the culprit behind the experimental inconsistencies in the literature has been found: the probe. “Our work has demonstrated a clear dependence of atomic-scale SPM experiments on the physical properties of the probe itself—namely, asymmetry and elasticity,” declared Dr. Baykara. “We were thus able to shed light on a number of controversial results in the literature, and have provided experimentalists a guide with which they can check the accuracy of their results.”
Dr. Baykara also pointed out another noteworthy aspect of the research. “This work has been conducted with substantial contributions from an undergraduate student, Berkin Uluutku. In our department, we place great importance on the participation of undergraduates in research projects. Berkin has been supported by TÜBİTAK’s 2209/A program, which is intended to foster undergraduate research at universities.”
The SPM research group’s cover article, “Artifacts Related to Tip Asymmetry in High-Resolution Atomic Force Microscopy and Scanning Tunneling Microscopy Measurements of Graphitic Surfaces,” may be found at http://dx.doi.org/10.1116/1.4915898.