Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > New photonic crystals have both electronic and optical properties

Using an epitaxial approach, researchers developed a 3-D photonic crystal LED, the first such optoelectronic device. | Graphic by Eric Nelson
Using an epitaxial approach, researchers developed a 3-D photonic crystal LED, the first such optoelectronic device. | Graphic by Eric Nelson

Abstract:
In an advance that could open new avenues for solar cells, lasers, metamaterials and more, researchers at the University of Illinois have demonstrated the first optoelectronically active 3-D photonic crystal.

New photonic crystals have both electronic and optical properties

Champaign, IL | Posted on July 25th, 2011

"We've discovered a way to change the three-dimensional structure of a well-established semiconductor material to enable new optical properties while maintaining its very attractive electrical properties," said Paul Braun, a professor of materials science and engineering and of chemistry who led the research effort.

The team published its advance in the journal Nature Materials.

Photonic crystals are materials that can control or manipulate light in unexpected ways thanks to their unique physical structures. Photonic crystals can induce unusual phenomena and affect photon behavior in ways that traditional optical materials and devices can't. They are popular materials of study for applications in lasers, solar energy, LEDs, metamaterials and more.

However, previous attempts at making 3-D photonic crystals have resulted in devices that are only optically active that is, they can direct light but not electronically active, so they can't turn electricity to light or vice versa.

The Illinois team's photonic crystal has both properties.

"With our approach to fabricating photonic crystals, there's a lot of potential to optimize electronic and optical properties simultaneously," said Erik Nelson, a former graduate student in Braun's lab who now is a postdoctoral researcher at Harvard University. "It gives you the opportunity to control light in ways that are very unique to control the way it's emitted and absorbed or how it propagates."

To create a 3-D photonic crystal that is both electronically and optically active, the researchers started with a template of tiny spheres packed together. Then, they deposit gallium arsenide (GaAs), a widely used semiconductor, through the template, filling in the gaps between the spheres.

The GaAs grows as a single crystal from the bottom up, a process called epitaxy. Epitaxy is common in industry to create flat, two-dimensional films of single-crystal semiconductors, but Braun's group developed a way to apply it to an intricate three-dimensional structure.

"The key discovery here was that we grew single-crystal semiconductor through this complex template," said Braun, who also is affiliated with the Beckman Institute for Advanced Science and Technology and with the Frederick Seitz Materials Research Laboratory at Illinois. "Gallium arsenide wants to grow as a film on the substrate from the bottom up, but it runs into the template and goes around it. It's almost as though the template is filling up with water. As long as you keep growing GaAs, it keeps filling the template from the bottom up until you reach the top surface."

The epitaxial approach eliminates many of the defects introduced by top-down fabrication methods, a popular pathway for creating 3-D photonic structures. Another advantage is the ease of creating layered heterostructures. For example, a quantum well layer could be introduced into the photonic crystal by partially filling the template with GaAs and then briefly switching the vapor stream to another material.

Once the template is full, the researchers remove the spheres, leaving a complex, porous 3-D structure of single-crystal semiconductor. Then they coat the entire structure with a very thin layer of a semiconductor with a wider bandgap to improve performance and prevent surface recombination.

To test their technique, the group built a 3-D photonic crystal LED the first such working device.

Now, Braun's group is working to optimize the structure for specific applications. The LED demonstrates that the concept produces functional devices, but by tweaking the structure or using other semiconductor materials, researchers can improve solar collection or target specific wavelengths for metamaterials applications or low-threshold lasers.

"From this point on, it's a matter of changing the device geometry to achieve whatever properties you want," Nelson said. It really opens up a whole new area of research into extremely efficient or novel energy devices.

The U.S. Department of Energy and the Army Research Office supported this work. Other Illinois faculty involved in the project are electrical and computer engineering professors James Coleman and Xiuling Li, and materials science and engineering professor John Rogers.

####

For more information, please click here

Contacts:
Liz Ahlberg
Physical Sciences Editor
217-244-1073


Paul Braun
217-244-7293

Copyright © University of Illinois at Urbana-Champaign

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

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

Simulations predict flat liquid May 21st, 2015

Display technology/LEDs/SS Lighting/OLEDs

Statement by QD Vision regarding European Parliament’s Vote on Cadmium-Based Quantum Dots May 20th, 2015

ORNL demonstrates first large-scale graphene fabrication May 14th, 2015

CLAIRE brings electron microscopy to soft materials: Berkeley researchers develop breakthrough technique for noninvasive nanoscale imaging May 14th, 2015

QD Vision to Showcase Quantum Dot “Firsts” at Display Week 2015: Executives will present, demo current and future quantum dot technology May 13th, 2015

Discoveries

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Nanotherapy effective in mice with multiple myeloma May 21st, 2015

Turn that defect upside down: Twin boundaries in lithium-ion batteries May 21st, 2015

Materials/Metamaterials

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

Supercomputer unlocks secrets of plant cells to pave the way for more resilient crops: IBM partners with University of Melbourne and UQ May 21st, 2015

Researchers develop new way to manufacture nanofibers May 21st, 2015

Taking control of light emission: Researchers find a way of tuning light waves by pairing 2 exotic 2-D materials May 20th, 2015

Announcements

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

New Antibacterial Wound Dressing in Iran Can Display Replacement Time May 22nd, 2015

Haydale Named Lead Sponsor for Cambridge Graphene Festival May 22nd, 2015

INSIDDE: Uncovering the real history of art using a graphene scanner May 21st, 2015

Energy

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

Sandia researchers first to measure thermoelectric behavior by 'Tinkertoy' materials May 20th, 2015

Industrial Nanotech, Inc. Announces Official Launch of the Eagle Platinum Tile™ May 19th, 2015

FEI and Weatherford Enter Into Joint Agreement for Advanced Reservoir Characterization Services May 18th, 2015

Photonics/Optics/Lasers

Samtec, Global Provider of Interconnect Systems, Joins IRT Nanoelec Silicon Photonics Program May 21st, 2015

Taking control of light emission: Researchers find a way of tuning light waves by pairing 2 exotic 2-D materials May 20th, 2015

Computing at the speed of light: Utah engineers take big step toward much faster computers May 18th, 2015

Wearables may get boost from boron-infused graphene: Rice U. researchers flex muscle of laser-written microsupercapacitors May 18th, 2015

Solar/Photovoltaic

Efficiency record for black silicon solar cells jumps to 22.1 percent: Aalto University's researchers improved their previous record by over 3 absolute percents in cooperation with Universitat Politècnica de Catalunya May 18th, 2015

Wearables may get boost from boron-infused graphene: Rice U. researchers flex muscle of laser-written microsupercapacitors May 18th, 2015

Random nanowire configurations increase conductivity over heavily ordered configurations May 16th, 2015

ORNL demonstrates first large-scale graphene fabrication May 14th, 2015

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