To technology insiders, graphene is a certified big deal. The one-atom thick carbon-based material elicits rhapsodic descriptions as the strongest, thinnest material known.
David L. Miller, NIST
Optical microscope image of a copper film mostly destroyed during graphene growth. What was a continuous copper film has decomposed into grey areas of bare sapphire, rings and irregular patches of copper that appear in a rainbow of colors due to oxidation, and small star-shaped islands of graphene, which appear bright because the graphene protects the copper from oxidation.
It also is light, flexible, and able to conduct electricity as well as copper. Graphene-based electronics promise advances such as faster internet speeds, cheaper solar cells, novel sensors, space suits spun from graphene yarn, and more.
Now a research team at the National Institute of Standards and Technology (NIST) in Boulder, Colo., may help bring graphene’s promise closer to reality. While searching for an ideal growth platform for the material, investigators developed a promising new recipe for a graphene substrate: a thin film of copper with massive crystalline grains. The team’s findings appear in the journal AIP Advances, which is produced by AIP Publishing.
The key advance is the grain size of the copper substrate. The large grains are several centimeters in size – lunkers by microelectronics standards – but their relative bulk enables them to survive the high temperatures needed for graphene growth, explained NIST researcher Mark Keller.
The inability of most copper films to survive this stage of graphene growth “has been one problem preventing wafer-scale production of graphene devices,” Keller said.
Thin films are an essential component of many electronic, optical, and medical technologies, but the grains in these films are typically smaller than one micrometer. To fabricate the new copper surface, whose grains are about 10,000 times larger, the researchers came up with a two-step process.
First, they deposited copper onto a sapphire wafer held slightly above room temperature. Second, they added the transformative step of annealing, or heat-treating, the film at a much higher temperature, near the melting point of copper. To demonstrate the viability of their giant-grained film, the researchers successfully grew graphene grains 0.2 millimeters in diameter on the new copper surface.
The article, "Giant secondary grain growth in Cu films on sapphire" by David L. Miller, Mark W. Keller, Justin M. Shaw, Katherine P. Rice, Robert R. Keller and Kyle M. Diederichsen appears in the journal AIP Advances. See: http://dx.doi.org/10.1063/1.4817829ABOUT THE JOURNAL
Jason Socrates Bardi | Newswise
Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says
19.07.2018 | Purdue University
Machine-learning predicted a superhard and high-energy-density tungsten nitride
18.07.2018 | Science China Press
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences