The study, published in the journal Science, could enable the use of new types of 2-D hybrid materials in technological applications and fundamental research.
ORNL and UT researchers have invented a method to merge different 2-dimensional materials into a seamless layer. This colorized scanning tunneling microscope image shows a single-atom sheet composed of graphene (seen in blue) combined with hexagonal boron nitride (seen in yellow).
By rethinking a traditional method of growing materials, the researchers combined two compounds -- graphene and boron nitride -- into a single layer only one atom thick. Graphene, which consists of carbon atoms arranged in hexagonal, honeycomb-like rings, has attracted waves of attention because of its high strength and electronic properties.
“People call graphene a wonder material that could revolutionize the landscape of nanotechnology and electronics,” ORNL’s An-Ping Li said. “Indeed, graphene has a lot of potential, but it has limits. To make use of graphene in applications or devices, we need to integrate graphene with other materials.”
One method to combine differing materials into heterostructures is epitaxy, in which one material is grown on top of another such that both have the same crystalline structure. To grow the 2-D materials, the ORNL-UT research team directed the growth process horizontally instead of vertically.
The researchers first grew graphene on a copper foil, etched the graphene to create clean edges, and then grew boron nitride through chemical vapor deposition. Instead of conforming to the structure of the copper base layer as in conventional epitaxy, the boron nitride atoms took on the crystallography of the graphene.
“The graphene piece acted as a seed for the epitaxial growth in two-dimensional space, so that the crystallography of the boron nitride is solely determined by the graphene,” UT’s Gong Gu said.
Not only did the team’s technique combine the two materials, it also produced an atomically sharp boundary, a one-dimensional interface, between the two materials. The ability to carefully control this interface, or “heterojunction,” is important from an applied and fundamental perspective, says Gu.
“If we want to harness graphene in an application, we have to make use of the interface properties, since as Nobel laureate Herbert Kroemer once said ‘the interface is the device,’” Li said. “By creating this clean, coherent, 1-D interface, our technique provides us with the opportunity to fabricate graphene-based devices for real applications.”
The new technique also allows researchers to experimentally investigate the scientifically intriguing graphene-boron nitride boundary for the first time.
“There is a vast body of theoretical literature predicting wonderful physical properties of this peculiar boundary, in absence of any experimental validation so far,” said Li, who leads an ORNL effort to study atomic-level structure-transport relationships using the lab’s unique four-probe scanning tunneling microscopy facility. “Now we have a platform to explore these properties.”
The research team anticipates that its method can be applied to other combinations of 2-D materials, assuming that the different crystalline structures are similar enough to match one another.
The study, titled “Heteroepitaxial Growth of Two-Dimensional Hexagonal Boron Nitride Templated by Graphene Edges,” is available online.
Coauthors are the University of Tennessee’s Gong Gu, Lei Liu, and Wan Deng; ORNL’s Jewook Park, Kendal Clark, Juan Carlos Idrobo, Leonardo Basile and An-Ping Li; and Sandia National Laboratories’ David Siegel and Kevin McCarty.
This work was partially supported by the National Science Foundation, the Defense Advanced Research Projects Agency, and the National Secretariat of Higher Education, Science, Technology and Innovation of Ecuador. Work at Sandia was supported by DOE’s Office of Science.
Part of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at ORNL by the Scientific User Facilities Division in DOE’s Office of Basic Energy Sciences. CNMS is one of the five DOE Nanoscale Science Research Centers supported by the DOE Office of Science, premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos national laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/.
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 http://science.energy.gov.
Morgan McCorkle | EurekAlert!
Could this material enable autonomous vehicles to come to market sooner?
20.06.2018 | University of Southern California
An unlikely marriage among oxides
20.06.2018 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
20.06.2018 | Information Technology
20.06.2018 | Materials Sciences
20.06.2018 | Life Sciences