Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > UCSB Researchers Uncover Transparency Limits on Transparent Conducting Oxides: Computational Materials researchers at UC Santa Barbara use cutting-edge calculations to determine fundamental optical transparency limits in conducting oxide material tin oxide

Three beams of light (red for infrared, yellow for visible light, and violet for ultraviolet) travel through a layer of SnO2. Absorption by the conduction electrons in the oxide reduces the intensity of the beams. Credit: Hartwin Peelaers, UCSB
Three beams of light (red for infrared, yellow for visible light, and violet for ultraviolet) travel through a layer of SnO2. Absorption by the conduction electrons in the oxide reduces the intensity of the beams.

Credit: Hartwin Peelaers, UCSB

Abstract:
Researchers in the Computational Materials Group at the University of California, Santa Barbara (UCSB) have uncovered the fundamental limits on optical transparency in the class of materials known as transparent conducting oxides. Their discovery will support development of energy efficiency improvements for devices that depend on optoelectronic technology, such as light- emitting diodes and solar cells.

UCSB Researchers Uncover Transparency Limits on Transparent Conducting Oxides: Computational Materials researchers at UC Santa Barbara use cutting-edge calculations to determine fundamental optical transparency limits in conducting oxide material tin oxide

Santa Barbara, CA | Posted on January 18th, 2012

Transparent conducting oxides are used as transparent contacts in a wide range of optoelectronic devices, such as photovoltaic cells, light-emitting diodes (LEDs), and LCD touch screens. These materials are unique in that they can conduct electricity while being transparent to visible light. For optoelectronic devices to be able to emit or absorb light, it is important that the electrical contacts at the top of the device are optically transparent. Opaque metals and most transparent materials lack the balance between these two characteristics to be functional for use in such technology.

In a paper published in Applied Physics Letters [APL 100, 011914 (2012)], the UCSB researchers used cutting-edge calculation methods to investigate tin dioxide (SnO2), a widely-used conducting oxide.

Conducting oxides strike an ideal balance between transparency and conductivity because their wide band gaps prevent absorption of visible light by excitation of electrons across the gap, according to the researchers. At the same time, dopant atoms provide additional electrons in the conduction band that enable electrical conductivity. However, these free electrons can also absorb light by being excited to higher conduction-band states.

"Direct absorption of visible light cannot occur in these materials because the next available electron level is too high in energy. But we found that more complex absorption mechanisms, which also involve lattice vibrations, can be remarkably strong", says Hartwin Peelaers, a postdoctoral researcher and the lead author of the paper. The other authors are Emmanouil Kioupakis, now at the University of Michigan, and Chris Van de Walle, a professor in the UCSB Materials Department and head of the research group.

They found that tin dioxide only weakly absorbs visible light, thus letting most light pass through, so that it is still a useful transparent contact. In their study, the transparency of SnO2 declined when moving to other wavelength regions. Absorption was 5 times stronger for ultraviolet light and 20 times stronger for the infrared light used in telecommunications.

"Every bit of light that gets absorbed reduces the efficiency of a solar cell or LED", remarked Chris Van de Walle. "Understanding what causes the absorption is essential for engineering improved materials to be used in more efficient devices."

Van de Walle's Computational Materials Group is affiliated with the College of Engineering at UCSB. Their research explores semiconducting binary oxides, nitride semiconductors, novel channel materials and dielectrics, materials for quantum computing, photochemical hydrogen generation, and metallic nanoparticles. Learn more about Computational Materials research at www.mrl.ucsb.edu/~vandewalle .

Their research was supported as part of the UCSB Center for Energy Efficient Materials, an Energy Frontier Research Center funded by the United States Department of Energy, by the Belgian American Educational Foundation, and by the UCSB Materials Research Laboratory: a National Science Foundation MRSEC.

####

For more information, please click here

Contacts:
Melissa Van De Werfhorst
Communications Manager
UCSB College of Engineering
(805) 893-4301

Copyright © University of California, Santa Barbara (UCSB)

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 Links

Faculty Profile - Chris Van de Walle:

UCSB Computation Materials Group:

Applied Physics Letters Paper:

Download this release as a .pdf:

Related News Press

News and information

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Copper shines as flexible conductor August 29th, 2014

Display technology/LEDs/SS Lighting/OLEDs

Copper shines as flexible conductor August 29th, 2014

LEDs made from ‘wonder material’ perovskite: Colourful LEDs made from a material known as perovskite could lead to LED displays which are both cheaper and easier to manufacture in future August 5th, 2014

Martini Tech Inc. becomes the exclusive distributor for Yoshioka Seiko Co. porous chucks for Europe and North America July 20th, 2014

Govt.-Legislation/Regulation/Funding/Policy

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Leading European communications companies and research organizations have launched an EU project developing the future 5th Generation cellular mobile networks August 28th, 2014

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

Chip Technology

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

Fonon Announces 3D Metal Sintering Technology: Emerging Additive Nano Powder Manufacturing Technology August 28th, 2014

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Announcements

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Energy

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Chemical reaction yields "tapes" of porphin molecules: Flexible tapes from the nanoworld August 13th, 2014

Solar/Photovoltaic

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing August 11th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE