Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

Large single-crystal graphene is possible
by Staff Writers
Seoul, South Korea (SPX) Jul 27, 2017

Using a new technique scientists obtained a single-crystal copper Cu(111) nucleus at the tapered end of the foil which gradually expanded to the full length of the foil in several minutes (b). This single-crystal copper foil was used as a substrate to grow graphene on its surface. The process of graphene crystallization started with small hexagonal islands of graphene crystals, which grew to cover the entire surface (c, from left to right). The dashed purple lines (c) show that the hexagonal graphene islands are parallel to each other: a key aspect for the success of the crystallization process. Image courtesy IBS, Peking University.

Boasting the conductivity, strength and flexibility we wished for, graphene was proposed as one of the most likely substitutes for silicon and other materials. Its launch into the market however is still slow. What is curbing graphene from industrial applications? One factor is that top quality single-crystal graphene produced so far is just a couple of millimeters or maximum centimeters in size.

Recently, a team led by Prof. Feng Ding and Prof. Rodney Ruoff at the Center for Multidimensional Carbon Materials within the Institute for Basic Science (IBS), Prof. Kaihui Liu at Peking University, and their collaborators reported the synthesis of a large sheet of monolayer single-crystal graphene.

This result allows a leap forward in graphene production: advancing from a technique that synthesizes a few cm2 sheet of single-crystal graphene in a couple of hours, to an optimized method that allows the creation of an almost-perfect (> 99.9 % aligned) 5 + 50 cm2 single-crystal graphene in just 20 minutes.

Moreover, the low production costs, comparable to commercially available lower quality polycrystalline graphene films, could expand its usability. Detailed in Science Bulletin, the method is expected to stimulate further fundamental work on graphene and related materials, including large scale folding of graphene sheets, similar to paper, creating origami-like or kirigami-like shapes, which could be applied to future flexible circuits.

A honeycomb-shaped monolayer of carbon atoms, uniform throughout the whole material, offers its exceptional properties to single-crystal graphene. On the other hand, polycrystalline graphene is formed by randomly oriented graphene islands, which decrease its quality. Currently, scientists are able to grow meter-sized polycrystalline graphene and smaller single-crystal graphene, ranging from 0.01 mm2 to a few cm2. The synthesis of large single-crystal graphene at a low cost has been considered a critical goal of graphene synthesis.

In this study, graphene is grown on the surface of a 5 + 50 cm2 copper foil, which was transformed into a single-crystal copper foil by heating to ~ 1,030?. A temperature slope from hot to cold moved the so-called grain boundary onwards, creating a perfect single-crystal.

In the heating and cooling treatment, copper atoms migrate inside the material, arranging into an ordered structure with fewer defects. "The secret to obtain single-crystal graphene of very large size, is to have a perfect single crystal copper as a base to start with. Large single-crystal copper foil is not available in the market, so labs must build it with their own means," explains Feng Ding, group leader at the Center for Multidimensional Carbon Materials.

Then, with another technique called chemical vapor deposition, millions of parallel graphene islands are formed on the copper foil surface. As more carbon atoms deposit on the foil, the islands keep on growing until they coalesce and form a very-close-to-perfect single-crystal graphene layer that covering the entire available surface.

In order to optimize the technique, the team had to consider four technical challenges: (i) preparation of single-crystal copper foil in a very large area, (ii) obtaining a high degree of alignment of the graphene islands following their nucleation and growth, (iii) seamlessly stitching the graphene islands into a single crystal through further growth and (iv) the fast growth of single-crystal graphene.

Although previous reports have addressed some of the above challenges, this study overcame all of them and made the synthesis of meter-sized single-crystal graphene possible. The degree of the misaligned graphene islands is less than 0.1%, thus great reduced defects and grain boundaries in the products.

The current result was limited only by the size of the copper foil and, in principle, both the size of the copper foil and graphene film could perhaps be unlimited. In addition, considering the very short time of graphene synthesis (20 minutes) and the relatively low-cost experimental setup, the price of a single-crystal (or nearly single-crystal) graphene could be close to that of current polycrystalline graphene films.

"The dream of many scientists is to make it the material of the future, to replace silicon," enthuses Ding. "Now we are exploring which is the best material to grow graphene on top and how to use copper as a substrate for other interesting 2D materials."

Research paper

Off Namibia, an underwater diamond harvest
Oranjenmund, Namibie (AFP) July 26, 2017
A vast mechanical monster rises from the Atlantic Ocean off the coast of Namibia, leaving a huge swell in its wake as seawater pours off its surface. The 285-tonne giant, dubbed "the butcher" by its operators, is diamond miner De Beers' hi-tech tool to collect the precious stones. After several hours of maintenance, the deep-sea vacuum is lowered again into the water on steel cables from ... read more

Related Links
Institute for Basic Science
Carbon Worlds - where graphite, diamond, amorphous, fullerenes meet

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Soyuz rocket rolled out, ready to launch

Astronauts gear up for space with tough Russian training

Russian sanctions won't affect cooperation in space

NASA Offers Space Station as Catalyst for Discovery in Washington

Vega to launch two Earth Observation Satellites for Italy, Israel and France

Three Up, Three Down as NASA Tests RS-25 Flight Controller

Iran in 'successful' test of satellite-launch rocket

Aerojet Rocketdyne's RS-25 Flight Controller Goes Three for Three in SLS Test

Portals to new worlds: Martian exploration near the North Pole

For Moratorium on Sending Commands to Mars, Blame the Sun

Tributes to wetter times on Mars

Opportunity will spend three weeks at current location due to Solar Conjunction

China develops sea launches to boost space commerce

Chinese satellite Zhongxing-9A enters preset orbit

Chinese Space Program: From Setback, to Manned Flights, to the Moon

Chinese Rocket Fizzles Out, Puts Other Launches on Hold

Good Night, Lisa Pathfinder

A Final Farewell to LISA Pathfinder

ASTROSCALE Raises a Total of $25 Million in Series C Led by Private Companies

LISA Pathfinder: bake, rattle and roll

Multitasking monolayers

Writing with the electron beam: Now in silver

Scientists announce the quest for high-index materials

A new synthesis route for alternative catalysts of noble metals

SETI Institute-Unistellar Partnership Promises to Revolutionize Amateur Astronomy

Holographic imaging could sample and identify living microbes in the outer solar system

Why looking for aliens is good for society

Breakthrough Starshot launches tiny spacecraft in quest for Alpha Centauri

New Horizons Video Soars over Pluto's Majestic Mountains and Icy Plains

Juno spots Jupiter's Great Red Spot

New evidence in support of the Planet Nine hypothesis

NASA's New Horizons Team Strikes Gold in Argentina

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement