The ability to determine the rotational orientation of graphene sheets and map strain is useful for understanding the electronic and transport properties of multiple layers of graphene, a one-atom thick form of carbon with potentially revolutionary semiconducting properties.
In digital photography, moiré (pronounced mwar-ray) patterns occur because of errors in the rendering process, which causes grid patterns to look wavy or distorted. Materials scientists have been using microscopic moiré patterns to detect stresses such as wrinkles or bulges in a variety of materials.
Researchers created graphene on the surface of a silicon carbide substrate at the Georgia Institute of Technology by heating one side so that only carbon, in the form of multilayer sheets of graphene, was left. Using a custom-built scanning tunneling microscope at NIST, the researchers were able to peer through the topmost layers of graphene to the layers beneath. This process, which the group dubbed "atomic moiré interferometry," enabled them to image the patterns created by the stacked graphene layers, which in turn allowed the group to model how the hexagonal lattices of the individual graphene layers were stacked in relation to one another.
Unlike other materials that tend to stretch out when they cool, graphene bunches up like a wrinkled bed sheet. The researchers were able to map these stress fields by comparing the relative distortion of the hexagons of carbon atoms that comprise the individual graphene layers. Their technique is so sensitive that it is able to detect strains in the graphene layers causing as little as a 0.1 percent change in atom spacing.
This collaboration between NIST and the Georgia Institute of Technology is part of a series of experiments aimed at gaining a fundamental understanding of the properties of graphene. Other examples of the group's work can been seen at www.mrs.org/s_mrs/bin.asp?CID=8684&DID=320520&DOC=FILE.PDF and www.mrs.org/s_mrs/bin.asp?CID=26616&DID=320529&DOC=FILE.PDF.
Their article, "Structural analysis of multilayer graphene via atomic moiré interferometry" was selected as an Editor's Highlight in Physical Review B for the month of March, 2010.
* D. Miller, K. Kubista, G. Rutter, M. Ruan, W. de Heer, P. First and J. Stroscio. Structural analysis of multilayer graphene via atomic moiré interferometry. Physical Review B. 81. 125427. Published March 24, 2010.
Mark Esser | EurekAlert!
Major discovery in controlling quantum states of single atoms
20.02.2018 | Institute for Basic Science
Observing and controlling ultrafast processes with attosecond resolution
20.02.2018 | Technische Universität München
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
20.02.2018 | Life Sciences
20.02.2018 | Medical Engineering
20.02.2018 | Physics and Astronomy