Refreshments are served at 3:00 p.m. in Physics room 242.
http://nano.anl.gov/docs/people/guisinger.pdf
The Center for Nanoscale Materials (CNM) at Argonne National Laboratory is one of five nanocenters supported by the DOE’s Nanoscale Science Research Center (NSRC) program. This talk will introduce the efforts and capabilities of the Scanning Probe Microscopy Group within the CNM, primarily focused on scanning tunneling microscopy (STM). The majority of this talk will focus on the controlled patterning of pristine graphene at the nanometer scale from an otherwise hydrogen saturated surface. We have found that the hydrogen saturation of graphene epitaxially grown on 4H:SiC(0001) is stable at room temperature and completely alters the original electronic properties which are no longer graphene-like. In addition to characterizing the structural and electronic properties of the surface at the atomic-scale, we have utilized the STM as a patterning tool via electron stimulated desorption of hydrogen, leaving behind regions of graphene. The STM enables a significant level of control and subsequent characterization of the graphene patterns at the highest resolution. With spectroscopic techniques we are able to extract electronic information of the patterned graphene regions. For patterned regions that are roughly 20 nm or greater, the inherent electronic properties of graphene are completely recovered. Below 20 nm we start to see dramatic variations in the electronic properties of the graphene as a function of pattern size.
