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

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

NanoSummit in Luxembourg: single wall carbon nanotubes have entered our lives as we approach a nanoaugmented future November 23rd, 2017

JPK reports on the exciting research in the School of Medicine at Sungkyunkwan University (SKKU), Suwon, South Korea using the NanoWizard® ULTRA Speed AFM to understand the binding of transcription factor Sox2 with super enhancers November 23rd, 2017

Precision NanoSystems to host nanomedicines roundtable November 23rd, 2017

Display technology/LEDs/SS Lighting/OLEDs

The next generation of power electronics? Gallium nitride doped with beryllium: How to cut down energy loss in power electronics? The right kind of doping November 9th, 2017

Atomic scale Moiré patterns to push electronic boundaries? November 1st, 2017

The secret to improving liquid crystal's mechanical performance: Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles October 13th, 2017

Missing atoms in a forgotten crystal bring luminescence October 10th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

EC Project Aims at Creating and Commercializing Cyber-Physical-System Solutions November 14th, 2017

Nanobiotix presented new clinical and pre-clinical data confirming NBTXR3’s significant potential role in Immuno-Oncology at SITC Annual Meeting November 14th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Discoveries

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Announcements

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

NanoSummit in Luxembourg: single wall carbon nanotubes have entered our lives as we approach a nanoaugmented future November 23rd, 2017

JPK reports on the exciting research in the School of Medicine at Sungkyunkwan University (SKKU), Suwon, South Korea using the NanoWizard® ULTRA Speed AFM to understand the binding of transcription factor Sox2 with super enhancers November 23rd, 2017

Precision NanoSystems to host nanomedicines roundtable November 23rd, 2017

Quantum Dots/Rods

Quantum communications bend to our needs: By changing the wavelengths of entangled photons to those used in telecommunications, researchers see quantum technology take a major leap forward September 28th, 2017

Band Gaps, Made to Order: Engineers create atomically thin superlattice materials with precision September 26th, 2017

New approach on research and design for CQD catalysts in World Scientific NANO August 2nd, 2017

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

Research partnerships

Nano Global, Arm Collaborate on Artificial Intelligence Chip to Drive Health Revolution by Capturing and Analyzing Molecular Data in Real Time November 21st, 2017

EC Project Aims at Creating and Commercializing Cyber-Physical-System Solutions November 14th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 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