Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Infrared LEDs can be made cheaper, compatible with silicon, say researchers

Abstract:
Light-emitting diodes at infrared wavelengths are the magic behind such things as night vision and optical communications, including the streaming data that comes through Netflix. Cornell researchers have advanced the process of making such LEDs cheaper and easier to fabricate, which could lead to ultra-thin LEDs painted onto silicon to replace computer wiring with light waves.

Infrared LEDs can be made cheaper, compatible with silicon, say researchers

Ithaca, NY | Posted on May 9th, 2012

The research group led by Frank Wise, professor of applied and engineering physics, reported online May 6 in the journal Nature Nanotechnology that they have used solution chemistry to make infrared LEDs out of nanocrystals, commonly known as quantum dots, out of lead sulfide.

Their process, which involves tuning emitted wavelengths based on controlling the size of the nanocrystals, could rival the effective, but expensive, practice of growing semiconductor materials using the atom-by-atom process known as epitaxy. The Cornell nanocrystal LEDs are about as bright as epitaxially grown LEDs, but they were made using low-temperature, solution-based processing that is much cheaper.

Infrared LEDs are usually made of crystals of such materials as indium gallium arsenide, and they cannot be grown on silicon due to their different crystal structures, Wise explained. Thus far there has been no natural way to make light-emitting materials on silicon.

Getting electrons to flow through nanocrystals is a major challenge, Wise said. The Cornell team did it with some clever chemistry: They changed the distance between the nanocrystals by changing the molecules on their surfaces. Longer carbon chains produced bigger spacing, which dramatically affected the efficiency of light emission. Changing the distance between nanocrystals by half a nanometer made the devices 100 times more efficient, Wise said. The researchers found the optimum distances between nanocrystals to make the LEDs emit the brightest light. They measured those distances using X-ray scattering technology provided by the Cornell High Energy Synchrotron Source (CHESS).

Because the Cornell-developed LEDs were made through solution processing, they can be more easily integrated with other materials. They could lead to such breakthroughs as the ability to "paint" the LEDs onto silicon, for example. Such an application would hold sway in optical interconnects, replacing electrical wires that are now a bottleneck for speed of the modern computer chip. Communication between chips with a light wave, rather than a wire, is expected to revolutionize information processing.

The nanocrystals the researchers used have struck interest among people making photovoltaic cells, too. A solar cell absorbs light and emits electrons as electric current, which can supply power. Lead sulfide and lead selenide nanocrystals are leading candidates for replacing cadmium telluride and other materials found in commercial solar cells today.

The paper's co-authors are Tobias Hanrath, assistant professor of chemical and biomolecular engineering, and George Malliaras, formerly an associate professor of materials science and engineering at Cornell; as well as former postdoctoral associate Liangfeng Sun; graduate students Joshua J. Choi, David Stachnik and Adam Bartnik (now a staff member at Wilson Laboratory); and postdoctoral associate Byung-Ryool Hyun.

The work was supported by the National Science Foundation, the KAUST-Cornell Center for Energy and Sustainability, the New York State Foundation for Science, Technology and Innovation and CHESS.

####

For more information, please click here

Contacts:
John Carberry
(607) 255-5353


Anne Ju


Chronicle Online
312 College Ave.
Ithaca, NY 14850
607.255.4206

http://www.news.cornell.edu

Copyright © Cornell 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

Physicists gain new insights into nanosystems with spherical confinement: Enormous potential for the targeted delivery of pharmaceutical agents and the creation of tailored nanoparticles July 27th, 2017

Strange electrons break the crystal symmetry of high-temperature superconductors: Brookhaven Lab scientists discover spontaneous voltage perpendicular to applied current that may help unravel the mystery of high-temperature superconductors July 27th, 2017

Getting closer to porous, light-responsive materials: A new flexible material changes its porous nature when exposed to light July 27th, 2017

First Capacitive Transducer with 13nm Gap July 27th, 2017

Display technology/LEDs/SS Lighting/OLEDs

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

Cambridge Nanotherm partners with Inabata for global sales and distribution June 20th, 2017

Leti Will Demo World’s-first WVGA 10-µm Pitch GaN Microdisplays for Augmented Reality Video at Display Week in Los Angles: Invited Paper also Will Present Leti’s Success with New Augmented Reality Technology That Reduces Pixel Pitch to Less than 5 Microns May 22nd, 2017

CCNY physicists demonstrate photonic hypercrystals for control of light-matter interaction May 5th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Strange electrons break the crystal symmetry of high-temperature superconductors: Brookhaven Lab scientists discover spontaneous voltage perpendicular to applied current that may help unravel the mystery of high-temperature superconductors July 27th, 2017

Graduate Students from Across the Country Attend Hands-on NanoCamp: Prominent scientists Warren Oliver, Ph.D., and George Pharr, Ph.D., presented a weeklong NanoCamp for hand-picked graduate students across the United States July 26th, 2017

Ultrathin device harvests electricity from human motion July 23rd, 2017

Semiliquid chains pulled out of a sea of microparticles July 20th, 2017

Discoveries

Physicists gain new insights into nanosystems with spherical confinement: Enormous potential for the targeted delivery of pharmaceutical agents and the creation of tailored nanoparticles July 27th, 2017

Strange electrons break the crystal symmetry of high-temperature superconductors: Brookhaven Lab scientists discover spontaneous voltage perpendicular to applied current that may help unravel the mystery of high-temperature superconductors July 27th, 2017

Getting closer to porous, light-responsive materials: A new flexible material changes its porous nature when exposed to light July 27th, 2017

First Capacitive Transducer with 13nm Gap July 27th, 2017

Announcements

Physicists gain new insights into nanosystems with spherical confinement: Enormous potential for the targeted delivery of pharmaceutical agents and the creation of tailored nanoparticles July 27th, 2017

Strange electrons break the crystal symmetry of high-temperature superconductors: Brookhaven Lab scientists discover spontaneous voltage perpendicular to applied current that may help unravel the mystery of high-temperature superconductors July 27th, 2017

Getting closer to porous, light-responsive materials: A new flexible material changes its porous nature when exposed to light July 27th, 2017

First Capacitive Transducer with 13nm Gap July 27th, 2017

Quantum Dots/Rods

Coupling a nano-trumpet with a quantum dot enables precise position determination July 14th, 2017

Graphene and quantum dots put in motion a CMOS-integrated camera that can see the invisible May 29th, 2017

The brighter side of twisted polymers: Conjugated polymers designed with a twist produce tiny, brightly fluorescent particles with broad applications May 16th, 2017

Nanoparticles open new window for biological imaging: “Quantum dots” that emit infrared light enable highly detailed images of internal body structures April 10th, 2017

Research partnerships

Strange electrons break the crystal symmetry of high-temperature superconductors: Brookhaven Lab scientists discover spontaneous voltage perpendicular to applied current that may help unravel the mystery of high-temperature superconductors July 27th, 2017

Getting closer to porous, light-responsive materials: A new flexible material changes its porous nature when exposed to light July 27th, 2017

Regulation of two-dimensional nanomaterials: New driving force for lithium-ion batteries July 26th, 2017

Studying Argon Gas Trapped in Two-Dimensional Array of Tiny "Cages": Understanding how individual atoms enter and exit the nanoporous frameworks could help scientists design new materials for gas separation and nuclear waste remediation July 17th, 2017

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