Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > New research findings open door to zinc-oxide-based UV lasers, LED devices

Abstract:
"Shallow acceptor complexes in p-type ZnO"

Authors: J.G. Reynolds, C. L. Reynolds, Jr., J.F. Muth, J.E. Rowe and D.E. Aspnes, North Carolina State University; A. Mohanta and H.O. Everitt, U.S. Army Aviation & Missile Research, Development & Engineering Center

Published: April 19, 2013, Applied Physics Letters

Abstract: We show that N-doped ZnO films grown on sapphire can exhibit significant (~1018 cm-3) room-temperature p-type behavior when sufficient nitrogen (N) is incorporated and the material is annealed appropriately. Substitutional N on the oxygen (O) sublattice is a deep acceptor; however, shallow acceptor complexes involve N, H and zinc vacancies (VZn). Combining secondary ion mass spectrometry, Raman-scattering, photoluminescence, and Hall-effect data, we establish the evolution of N from its initial incorporation on a Zn site to a final shallow acceptor complex VZn_NO_H+ with an ionization energy of ca. 130 meV. This complex is responsible for the observed p-type behavior.

New research findings open door to zinc-oxide-based UV lasers, LED devices

Raleigh, NC | Posted on April 23rd, 2013

Researchers from North Carolina State University have solved a long-standing materials science problem, making it possible to create new semiconductor devices using zinc oxide (ZnO) - including efficient ultraviolet (UV) lasers and LED devices for use in sensors and drinking water treatment, as well as new ferromagnetic devices.

"The challenge of using ZnO to make these devices has stumped researchers for a long time, and we've developed a solution that uses some very common elements: nitrogen, hydrogen and oxygen," says Dr. Lew Reynolds, co-author of a paper describing the research and a teaching associate professor of materials science and engineering at NC State. "We've shown that it can be done, and how it can be done - and that opens the door to a suite of new UV laser and LED technologies," says Dr. Judith Reynolds, a research scientist at NC State and lead author of the paper.

To make laser and LED technologies, you need both "n-type" materials and "p-type" materials. N-type materials contain an abundance of free electrons. P-type materials have "holes" that attract those free electrons. But the holes in the p-type materials have a lower energy state, which means that electrons release their excess energy in the form of light as they travel from the n-type material to the p-type material. The shedding of excess energy at the so-called "p-n junction" is what produces light in lasers and LED devices.

Researchers have been interested in using ZnO to create these devices because ZnO produces UV light, and because ZnO can be used to make devices with relatively fewer unwanted defects than other UV emitters- which means the resulting lasers or LEDs would be more energy efficient.

However, researchers had been unable to consistently produce stable p-type materials out of ZnO. Now researchers have solved that problem by introducing a specific "defect complex," via a unique set of growth and annealing procedures, in the ZnO. The defect complex looks different from a normal ZnO molecule. The zinc atom is missing and a nitrogen atom (attached to a hydrogen atom) substitutes for the oxygen atom. These defect complexes are dispersed throughout the ZnO material and serve as the "holes" that accept the electrons in p-type materials.

Not only does the research illustrate how to create p-type materials from ZnO, but the defect complex allows the ZnO p-n junction to function efficiently - and produce UV light - at room temperature.

The paper, "Shallow acceptor complexes in p-type ZnO, " is published online in Applied Physics Letters. Lead author of the paper is Dr. Judith Reynolds, a research scientist at NC State. Co-authors include Drs. A. Mohanta and H.O. Everitt of the U.S. Army Aviation & Missile Research, Development & Engineering Center; Dr. John Muth, a professor of electrical and computer engineering at NC State; Dr. John Rowe, a research professor of physics at NC State; and Dr. David Aspnes, Distinguished University Professor of Physics at NC State. The research was supported by the Defense Advanced Research Projects Agency.

####

For more information, please click here

Contacts:
Matt Shipman

919-515-6386

Dr. Lewis Reynolds

919.515.7622

Copyright © North Carolina State 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 Links

Download article:

Related News Press

News and information

Ageing can drive progress: Population ageing is likely to boost medicine, nanotechnology and robotics, but increase political risks July 27th, 2016

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Researchers develop faster, precise silica coating process for quantum dot nanorods July 12th, 2016

Integrated trio of 2-D nanomaterials unlocks graphene electronics applications: Voltage-controlled oscillator developed at UC Riverside could be used in thousands of applications from computers to wearable technologies July 7th, 2016

GraphExeter illuminates bright new future for flexible lighting devices June 23rd, 2016

New nanomaterial offers promise in bendable, wearable electronic devices: Electroplated polymer makes transparent, highly conductive, ultrathin film June 13th, 2016

Govt.-Legislation/Regulation/Funding/Policy

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Sensors

Ultrasensitive sensor using N-doped graphene July 26th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Electron 'spin control' of levitated nanodiamonds could bring advances in sensors, quantum information processing July 20th, 2016

Easier, faster, cheaper: A full-filling approach to making nanotubes of consistent quality: Approach opens a straightforward route for engineering the properties of single-wall carbon nanotubes July 19th, 2016

Discoveries

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Scientists test nanoparticle drug delivery in dogs with osteosarcoma July 26th, 2016

Materials/Metamaterials

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics July 25th, 2016

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

Announcements

Ageing can drive progress: Population ageing is likely to boost medicine, nanotechnology and robotics, but increase political risks July 27th, 2016

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

Enhancing molecular imaging with light: New technology platform increases spectroscopic resolution by 4 fold July 27th, 2016

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Military

Ultrasensitive sensor using N-doped graphene July 26th, 2016

Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics July 25th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Water

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

Electricity generated with water, salt and a 3-atoms-thick membrane: EPFL researchers have developed a system that generates electricity from osmosis with unparalleled efficiency. Their work, featured in Nature, uses seawater, fresh water, and a new type of membrane just 3 atoms July 15th, 2016

Bouncing droplets remove contaminants like pogo jumpers: Researchers at Duke University and the University of British Columbia are exploring whether surfaces can shed dirt without being subjected to fragile coatings July 7th, 2016

Mille-feuille-filter removes viruses from water May 19th, 2016

Photonics/Optics/Lasers

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

RMIT researchers make leap in measuring quantum states July 21st, 2016

The birth of quantum holography: Making holograms of single light particles! July 21st, 2016

Graphene photodetectors: Thinking outside the 2-D box July 21st, 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







Car Brands
Buy website traffic