Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

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

Novel Rocket Design Flight Tested: New Rocket Propellant and Motor Design Offers High Performance and Safety October 23rd, 2014

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Nanoparticle technology triples the production of biogas October 23rd, 2014

SUNY Polytechnic Institute Invites the Public to Attend its Popular Statewide 'NANOvember' Series of Outreach and Educational Events October 23rd, 2014

Display technology/LEDs/SS Lighting/OLEDs

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

QD Vision Wins Prestigious Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency October 16th, 2014

Beyond LEDs: Brighter, new energy-saving flat panel lights based on carbon nanotubes - Planar light source using a phosphor screen with highly crystalline single-walled carbon nanotubes (SWCNTs) as field emitters demonstrates its potential for energy-efficient lighting device October 14th, 2014

Aledia’s Nanowire LED Technology Endorsed By 2014 Physics Nobel Prize Winner: Hiroshi Amano Serves on Company’s Scientific Advisory Board October 13th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Novel Rocket Design Flight Tested: New Rocket Propellant and Motor Design Offers High Performance and Safety October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Brookhaven Lab Launches Computational Science Initiative:Leveraging computational science expertise and investments across the Laboratory to tackle "big data" challenges October 22nd, 2014

Bipolar Disorder Discovery at the Nano Level: Tiny structures found in brain synapses help scientists better understand disorder October 22nd, 2014

Sensors

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Journal Nanotechnology Progress International (JONPI), 2014, Volume 5, Issue 1, pp 1-24 October 22nd, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Graphenea opens US branch October 16th, 2014

Discoveries

Iranian Scientists Apply Nanotechnology to Produce Surgery Suture October 23rd, 2014

Iranian, Malaysian Scientists Study Nanophotocatalysts for Water Purification October 23rd, 2014

Nanoparticle technology triples the production of biogas October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Materials/Metamaterials

Researchers patent a nanofluid that improves heat conductivity October 22nd, 2014

Materials for the next generation of electronics and photovoltaics: MacArthur Fellow develops new uses for carbon nanotubes October 21st, 2014

Super stable garnet ceramics may be ideal for high-energy lithium batteries October 21st, 2014

Could I squeeze by you? Ames Laboratory scientists model molecular movement within narrow channels of mesoporous nanoparticles October 21st, 2014

Announcements

Nanoparticle technology triples the production of biogas October 23rd, 2014

SUNY Polytechnic Institute Invites the Public to Attend its Popular Statewide 'NANOvember' Series of Outreach and Educational Events October 23rd, 2014

Advancing thin film research with nanostructured AZO: Innovnano’s unique and cost-effective AZO sputtering targets for the production of transparent conducting oxides October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Military

NanoTechnology for Defense (NT4D) October 22nd, 2014

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

1980s aircraft helps quantum technology take flight October 20th, 2014

Water

Iranian, Malaysian Scientists Study Nanophotocatalysts for Water Purification October 23rd, 2014

New Nanocomposites Help Elimination of Toxic Dyes October 15th, 2014

Fast, cheap nanomanufacturing: Arrays of tiny conical tips that eject ionized materials could fabricate nanoscale devices cheaply October 4th, 2014

Production of Filters for Separation of Water from Petroleum Products in Iran October 1st, 2014

Photonics/Optics/Lasers

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

IRLYNX and CEA-Leti to Streamline New CMOS-based Infrared Sensing Modules Dedicated to Human-activities Characterization October 15th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 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