Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

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

Searching for a nanotech self-organizing principle May 1st, 2016

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Manipulating light inside opaque layers April 24th, 2016

Highlights from the Graphene Flagship April 22nd, 2016

What screens are made of: New twists (and bends) in LCD research: X-ray research at Berkeley Lab details exotic structure formed by liquid crystals April 19th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Sensors

Electrically Conductive Graphene Ink Enables Printing of Biosensors April 23rd, 2016

Highlights from the Graphene Flagship April 22nd, 2016

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

With simple process, UW-Madison engineers fabricate fastest flexible silicon transistor April 21st, 2016

Discoveries

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Materials/Metamaterials

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Atomic magnets using hydrogen and graphene April 27th, 2016

Announcements

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Military

Nanograft seeded with 3 cell types promotes blood vessel formation to speed wound healing April 27th, 2016

The light stuff: A brand-new way to produce electron spin currents - Colorado State University physicists are the first to demonstrate using non-polarized light to produce a spin voltage in a metal April 26th, 2016

NRL reveals novel uniform coating process of p-ALD April 21st, 2016

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Water

Novel anti-biofilm nano coating developed at Ben-Gurion U.: Offers significant anti-adhesive potential for a variety of medical and industrial applications April 25th, 2016

Adding some salt to the recipe for energy storage materials: Researchers use common table salt as growth template April 22nd, 2016

NRL reveals novel uniform coating process of p-ALD April 21st, 2016

Researchers create perfect nanoscrolls from graphene’s imperfect form April 14th, 2016

Photonics/Optics/Lasers

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

NREL theory establishes a path to high-performance 2-D semiconductor devices April 27th, 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