With unique properties and potential applications in areas from electronics to biodevices, graphene, which consists of a single sheet of carbon atoms, has been hailed as a rising star in the materials world.
Now, an ORNL study published in Nature Nanotechnology suggests that point defects, composed of silicon atoms that replace individual carbon atoms in graphene, could aid attempts to transfer data on an atomic scale by coupling light with electrons.
“In this proof of concept experiment, we have shown that a tiny wire made up of a pair of single silicon atoms in graphene can be used to convert light into an electronic signal, transmit the signal and then convert the signal back into light,” said coauthor Juan-Carlos Idrobo, who holds a joint appointment at ORNL and Vanderbilt University.
An ORNL-led team discovered this novel behavior by using aberration-corrected scanning transmission electron microscopy to image the plasmon response, or optical-like signals, of the point defects. The team’s analysis found that the silicon atoms act like atomic-sized antennae, enhancing the local surface plasmon response of graphene, and creating a prototypical plasmonic device.
“The idea with plasmonic devices is that they can convert optical signals into electronic signals,” Idrobo said. “So you could make really tiny wires, put light in one side of the wire, and that signal will be transformed into collective electron excitations known as plasmons. The plasmons will transmit the signal through the wire, come out the other side and be converted back to light.”
Although other plasmonic devices have been demonstrated, previous research in surface plasmons has been focused primarily on metals, which has limited the scale at which the signal transfer occurs.
“When researchers use metal for plasmonic devices, they can usually only get down to 5 - 7 nanometers,” said coauthor Wu Zhou. “But when you want to make things smaller, you always want to know the limit. Nobody thought we could get down to a single atom level.”
In-depth analysis at the level of a single atom was made possible through the team’s access to an electron microscope that is part of ORNL’s Shared Research Equipment (ShaRE) User Facility.
“It is the one of only a few electron microscopes in the world that we can use to look at and study materials and obtain crystallography, chemistry, bonding, optical and plasmon properties at the atomic scale with single atom sensitivity and at low voltages,” Idrobo said. “This is an ideal microscope for people who want to research carbon-based materials, such as graphene.”
In addition to its microscopic observations, the ORNL team employed theoretical first-principles calculations to confirm the stability of the observed point defects. The full paper, titled “Atomically Localized Plasmon Enhancement in Monolayer Graphene,” is available online here: http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2011.252.html.
Coauthors are ORNL’s Jagjit Nanda; and Jaekwang Lee, Sokrates Pantelides and Stephen Pennycook, who are jointly affiliated with ORNL and Vanderbilt. The research was supported by DOE’s Office of Science, which also sponsors ORNL’s ShaRE User Facility; by the National Science Foundation; and by the McMinn Endowment at Vanderbilt University. The study used resources of the National Energy Research Scientific Computer Center, which is supported by DOE’S Office of Science.
ORNL is managed by UT-Battelle for the Department of Energy's Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Caption: Electron microscopy at Oak Ridge National Laboratory has demonstrated that silicon atoms (seen in white) can act like "atomic antennae" in graphene to transmit an electronic signal at the atomic scale.NOTE TO EDITORS: You may read other press releases from Oak Ridge National Laboratory or learn more about the lab at http://www.ornl.gov/news. Additional information about ORNL is available at the sites below:
Morgan McCorkle | Newswise Science News
Custom sequences for polymers using visible light
22.03.2018 | Tokyo Metropolitan University
The search for dark matter widens
21.03.2018 | American Institute of Physics
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences