Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Graphane yields new potential

Rice researchers created these fanciful images of electron densities from their graphane-embedded quantum dot calculations. The isosurfaces depict electrons in the valance band that, in reality, would be confined within the quantum dot, and demonstrate that very little charge would leak from the hydrogen-defined boundaries of such a dot. CREDIT: EVGENI PENEV/ABHISHEK SINGH
Rice researchers created these fanciful images of electron densities from their graphane-embedded quantum dot calculations. The isosurfaces depict electrons in the valance band that, in reality, would be confined within the quantum dot, and demonstrate that very little charge would leak from the hydrogen-defined boundaries of such a dot. CREDIT: EVGENI PENEV/ABHISHEK SINGH

Abstract:
Rice physicists dig theoretical wells to mine quantum dots

Graphane yields new potential

Houston, TX | Posted on May 25th, 2010

Graphane is the material of choice for physicists on the cutting edge of materials science, and Rice University researchers are right there with the pack - and perhaps a little ahead.

Researchers mentored by Boris Yakobson, a Rice professor of mechanical engineering and materials science and of chemistry, have discovered the strategic extraction of hydrogen atoms from a two-dimensional sheet of graphane naturally opens up spaces of pure graphene that look - and act - like quantum dots.

That opens up a new world of possibilities for an ever-shrinking class of nanoelectronics that depend on the highly controllable semiconducting properties of quantum dots, particularly in the realm of advanced optics.

The theoretical work by Abhishek Singh and Evgeni Penev, both postdoctoral researchers in co-author Yakobson's group, was published online last week in the journal ACS Nano and will be on the cover of the print version in June. Rice was recently named the world's No. 1 institution for materials science research by a United Kingdom publication.

Graphene has become the Flat Stanley of materials. The one-atom-thick, honeycomb-like form of carbon may be two-dimensional, but it seems to be everywhere, touted as a solution to stepping beyond the limits of Moore's Law.

Graphane is simply graphene modified by hydrogen atoms added to both sides of the matrix, which makes it an insulator. While it's still technically only a single atom thick, graphane offers great possibilities for the manipulation of the material's semiconducting properties.

Quantum dots are crystalline molecules from a few to many atoms in size that interact with light and magnetic fields in unique ways. The size of a dot determines its band gap - the amount of energy needed to close the circuit - and makes it tunable to a precise degree. The frequencies of light and energy released by activated dots make them particularly useful for chemical sensors, solar cells, medical imaging and nanoscale circuitry.

Singh and Penev calculated that removing islands of hydrogen from both sides of a graphane matrix leaves a well with all the properties of quantum dots, which may also be useful in creating arrays of dots for many applications.

"We arrived at these ideas from an entirely different study of energy storage in a form of hydrogen adsorption on graphene," Yakobson said. "Abhishek and Evgeni realized that this phase transformation (from graphene to graphane), accompanied by the change from metal to insulator, offers a novel palette for nanoengineering."

Their work revealed several interesting characteristics. They found that when chunks of the hydrogen sublattice are removed, the area left behind is always hexagonal, with a sharp interface between the graphene and graphane. This is important, they said, because it means each dot is highly contained; calculations show very little leakage of charge into the graphane host material. (How, precisely, to remove hydrogen atoms from the lattice remains a question for materials scientists, who are working on it, they said.)

"You have an atom-like spectra embedded within a media, and then you can play with the band gap by changing the size of the dot," Singh said. "You can essentially tune the optical properties."

Along with optical applications, the dots may be useful in single-molecule sensing and could lead to very tiny transistors or semiconductor lasers, he said.

Challenges remain in figuring out how to make arrays of quantum dots in a sheet of graphane, but neither Singh nor Penev sees the obstacles as insurmountable.

"We think the major conclusions in the paper are enough to excite experimentalists," said Singh, who will soon leave Rice to become an assistant professor at the Indian Institute of Science in Bangalore. "Some are already working in the directions we explored."

"Their work is actually supporting what we're suggesting, that you can do this patterning in a controlled way," Penev said.

When might their calculations bear commercial fruit? "That's a tough question," Singh said. "It won't be that far, probably -- but there are challenges. I don't know that we can give it a time frame, but it could happen soon."

Funding from the Office of Naval Research supported the work. Computations were performed at the Department of Defense Supercomputing Resource Center at the Air Force Research Laboratory.

####

About Rice University
Located in Houston, Rice University is consistently ranked one of America's best teaching and research universities. Known for its "unconventional wisdom," Rice is distinguished by its: size -- 3,102 undergraduates and 2,237 graduate students; selectivity -- 12 applicants for each place in the freshman class; resources -- an undergraduate student-to-faculty ratio of 5-to-1; sixth largest endowment per student among American private research universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work.

For more information, please click here

Contacts:
David Ruth
713-348-6327

Copyright © Rice University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

Explaining how 2-D materials break at the atomic level January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Govt.-Legislation/Regulation/Funding/Policy

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Strength of hair inspires new materials for body armor January 18th, 2017

Self-assembling particles brighten future of LED lighting January 18th, 2017

Possible Futures

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

Explaining how 2-D materials break at the atomic level January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Academic/Education

Oxford Nanoimaging report on how the Nanoimager, a desktop microscope delivering single molecule, super-resolution performance, is being applied at the MRC Centre for Molecular Bacteriology & Infection November 22nd, 2016

The University of Applied Sciences in Upper Austria uses Deben tensile stages as an integral part of their computed tomography research and testing facility October 18th, 2016

Enterprise In Space Partners with Sketchfab and 3D Hubs for NewSpace Education October 13th, 2016

New Agricultural Research Center Debuts at UCF October 12th, 2016

Nanotubes/Buckyballs/Fullerenes

Captured on video: DNA nanotubes build a bridge between 2 molecular posts: Research may lead to new lines of direct communication with cells January 9th, 2017

Nano-chimneys can cool circuits: Rice University scientists calculate tweaks to graphene would form phonon-friendly cones January 4th, 2017

WPI researchers build liquid biopsy chip that detects metastatic cancer cells in blood December 15th, 2016

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Nanoelectronics

Nano-chimneys can cool circuits: Rice University scientists calculate tweaks to graphene would form phonon-friendly cones January 4th, 2017

Advance in intense pulsed light sintering opens door to improved electronics manufacturing December 23rd, 2016

Fast track control accelerates switching of quantum bits December 16th, 2016

GLOBALFOUNDRIES Demonstrates Industry-Leading 56Gbps Long-Reach SerDes on Advanced 14nm FinFET Process Technology: Proven ASIC IP solution will enable significant performance and power efficiency improvements for next-generation high-speed applications December 13th, 2016

Announcements

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

New research helps to meet the challenges of nanotechnology: Research helps to make the most of nanoscale catalytic effects for nanotechnology January 20th, 2017

Ultra-precise chip-scale sensor detects unprecedentedly small changes at the nanoscale January 20th, 2017

Quantum Dots/Rods

Carbon dots dash toward 'green' recycling role: Rice scientists, colleagues use doped graphene quantum dots to reduce carbon dioxide to fuel December 18th, 2016

Two electrons go on a quantum walk and end up in a qudit: Russian scientists find a way to reliably connect quantum elements December 13th, 2016

Trickling electrons: Close to absolute zero, the particles exhibit their quantum nature November 10th, 2016

Notre Dame researchers find transition point in semiconductor nanomaterials September 6th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project