Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Laser technique could unlock use of tough material for next-generation electronics

31.05.2019

Researchers make graphene tunable, opening up its band gap to a record 2.1 electronvolts

In 2004, researchers discovered a super thin material that is at least a 100 times stronger than steel and the best known conductor of heat and electricity.


Graphene, a super tough wonder material, hasn't made it into electronics yet because it doesn't conduct an electric current on its own. Researchers used a laser technique to permanently stress graphene into a structure that allows the flow of electric current.

Credit: Purdue University image/Gary Cheng

This means that the material, graphene, could bring faster electronics than is possible today with silicon.

But to truly be useful, graphene would need to carry an electric current that switches on and off, like what silicon does in the form of billions of transistors on a computer chip. This switching creates strings of 0s and 1s that a computer uses for processing information.

Purdue University researchers, in collaboration with the University of Michigan and the Huazhong University of Science and Technology, show how a laser technique could permanently stress graphene into having a structure that allows the flow of electric current.

This structure is a so-called "band gap." Electrons need to jump across this gap in order to become conduction electrons, which makes them capable of carrying electric current. But graphene doesn't naturally have a band gap.

Purdue researchers created and widened the band gap in graphene to a record 2.1 electronvolts. To function as a semiconductor such as silicon, the band gap would need to be at least the previous record of 0.5 electronvolts.

"This is the first time that an effort has achieved such high band gaps without affecting graphene itself, such as through chemical doping. We have purely strained the material," said Gary Cheng, professor of industrial engineering at Purdue, whose lab has investigated various ways to make graphene more useful for commercial applications.

The presence of a band gap allows semiconductor materials to switch between insulating or conducting an electric current, depending on whether their electrons are pushed across the band gap or not.

Surpassing 0.5 electronvolts unlocks even more potential for graphene in next-generation electronic devices, the researchers say. Their work appears in an issue of Advanced Materials.

"Researchers in the past opened the band gap by simply stretching graphene, but stretching alone doesn't widen the band gap very much. You need to permanently change the shape of graphene to keep the band gap open," Cheng said.

Cheng and his collaborators not only kept the band gap open in graphene, but also made it to where the gap width could be tuned from zero to 2.1 electronvolts, giving scientists and manufacturers the option to just use certain properties of graphene depending on what they want the material to do.

The researchers made the band gap structure permanent in graphene using a technique called laser shock imprinting, which Cheng developed in 2014 along with scientists at Harvard University, the Madrid Institute for Advanced Studies and the University of California, San Diego.

For this study, the researchers used a laser to create shockwave impulses that penetrated an underlying sheet of graphene. The laser shock strains graphene onto a trench-like mold - permanently shaping it. Adjusting the laser power adjusts the band gap.

While still far from putting graphene into semiconducting devices, the technique grants more flexibility in taking advantage of the material's optical, magnetic and thermal properties, Cheng said.

###

The work was supported by multiple entities, including the National Science Foundation (Grant numbers CMMI-0547636 and CMMI 0928752) and the National Research Council Senior Research Associateship.

ABSTRACT

Asymmetric 3D Elastic-Plastic Strain-Modulated Electron Energy Structure in Monolayer Graphene by Laser Shocking

Maithilee Motlag1, Prashant Kumar1, Kevin Y. Hu1, Shengyu Jin1, Ji Li1, Jiayi Shao1, Xuan Yi1, Yen-Hsiang Lin2, Jenna C. Walrath2, Lei Tong3, Xinyu Huang3, Rachel S. Goldman2, Lei Ye3, and Gary J. Cheng1

1Purdue University, West Lafayette, IN, USA

2University of Michigan, Ann Arbor, MI, USA

3Huazhong University of Science and Technology, Wuhan, China

doi: 10.1002/adma.201900597

Graphene has a great potential to replace silicon in prospective semiconductor industries due to its outstanding electronic and transport properties; nonetheless, its lack of energy bandgap is a substantial limitation for practical applications. To date, straining graphene to break its lattice symmetry is perhaps the most efficient approach toward realizing bandgap tunability in graphene. However, due to the weak lattice deformation induced by uniaxial or in?plane shear strain, most strained graphene studies have yielded bandgaps <1 eV. In this work, a modulated inhomogeneous local asymmetric elastic-plastic straining is reported that utilizes GPa?level laser shocking at a high strain rate (dε/dt) ? 106-107 s?1, with excellent formability, inducing tunable bandgaps in graphene of up to 2.1 eV, as determined by scanning tunneling spectroscopy. High?resolution imaging and Raman spectroscopy reveal strain?induced modifications to the atomic and electronic structure in graphene and first?principles simulations predict the measured bandgap openings. Laser shock modulation of semimetallic graphene to a semiconducting material with controllable bandgap has the potential to benefit the electronic and optoelectronic industries.

Media Contact

Kayla Wiles
wiles5@purdue.edu
765-494-2432

 @PurdueUnivNews

http://www.purdue.edu/ 

Kayla Wiles | EurekAlert!
Further information:
https://www.purdue.edu/newsroom/releases/2019/Q2/laser-technique-could-unlock-use-of-tough-material-for-next-generation-electronics.html
http://dx.doi.org/10.1002/adma.201900597

More articles from Materials Sciences:

nachricht A sustainable new material for carbon dioxide capture
09.12.2019 | Chalmers University of Technology

nachricht A robot and software make it easier to create advanced materials
06.12.2019 | Rutgers University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electronic map reveals 'rules of the road' in superconductor

Band structure map exposes iron selenide's enigmatic electronic signature

Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

The Arctic atmosphere - a gathering place for dust?

09.12.2019 | Earth Sciences

New ultra-miniaturized scope less invasive, produces higher quality images

09.12.2019 | Information Technology

Discovery of genes involved in the biosynthesis of antidepressant

09.12.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>