Subscribe free to our newsletters via your
. 24/7 Space News .




ENERGY TECH
Scientists craft atomically seamless semiconductor junctions
by Staff Writers
Seattle WA (SPX) Aug 28, 2014


This photoluminescence intensity map shows a typical piece of the lateral heterostructures. The junction region produces an enhanced light emission, indicating its application potential in optoelectronics. Image courtesy Uni of Washington.

Scientists have developed what they believe is the thinnest-possible semiconductor, a new class of nanoscale materials made in sheets only three atoms thick.

The University of Washington researchers have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction. This result could be the basis for next-generation flexible and transparent computing, better light-emitting diodes, or LEDs, and solar technologies.

"Heterojunctions are fundamental elements of electronic and photonic devices," said senior author Xiaodong Xu, a UW assistant professor of materials science and engineering and of physics.

"Our experimental demonstration of such junctions between two-dimensional materials should enable new kinds of transistors, LEDs, nanolasers, and solar cells to be developed for highly integrated electronic and optical circuits within a single atomic plane."

The research was published online this week in Nature Materials.

The researchers discovered that two flat semiconductor materials can be connected edge-to-edge with crystalline perfection. They worked with two single-layer, or monolayer, materials - molybdenum diselenide and tungsten diselenide - that have very similar structures, which was key to creating the composite two-dimensional semiconductor.

Collaborators from the electron microscopy center at the University of Warwick in England found that all the atoms in both materials formed a single honeycomb lattice structure, without any distortions or discontinuities. This provides the strongest possible link between two single-layer materials, necessary for flexible devices. Within the same family of materials it is feasible that researchers could bond other pairs together in the same way.

The researchers created the junctions in a small furnace at the UW. First, they inserted a powder mixture of the two materials into a chamber heated to 900 degrees Celsius (1,652 F). Hydrogen gas was then passed through the chamber and the evaporated atoms from one of the materials were carried toward a cooler region of the tube and deposited as single-layer crystals in the shape of triangles.

After a while, evaporated atoms from the second material then attached to the edges of the triangle to create a seamless semiconducting heterojunction.

"This is a scalable technique," said Sanfeng Wu, a UW doctoral student in physics and one of the lead authors. "Because the materials have different properties, they evaporate and separate at different times automatically. The second material forms around the first triangle that just previously formed. That's why these lattices are so beautifully connected."

With a larger furnace, it would be possible to mass-produce sheets of these semiconductor heterostructures, the researchers said. On a small scale, it takes about five minutes to grow the crystals, with up to two hours of heating and cooling time.

"We are very excited about the new science and engineering opportunities provided by these novel structures," said senior author David Cobden, a UW professor of physics.

"In the future, combinations of two-dimensional materials may be integrated together in this way to form all kinds of interesting electronic structures such as in-plane quantum wells and quantum wires, superlattices, fully functioning transistors, and even complete electronic circuits."

The researchers have already demonstrated that the junction interacts with light much more strongly than the rest of the monolayer, which is encouraging for optoelectric and photonic applications like solar cells.

Other co-authors are Chunming Huang and Pasqual Rivera of UW physics; Ana Sanchez, Richard Beanland and Jonathan Peters at the University of Warwick; Jason Ross of UW materials science and engineering; and Wang Yao, a theoretical physicist of the University of Hong Kong.

This research was funded by the U.S. Department of Energy, the UW's Clean Energy Institute, the Research Grant Council of Hong Kong, the University Grants Committee of Hong Kong, the Croucher Foundation, the Science City Research Alliance and the Higher Education Funding Council for England's Strategic Development Fund.

.


Related Links
University of Washington
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ENERGY TECH
Scientists uncover clues to role of magnetism in iron-based superconductors
Oak Ridge TN (SPX) Aug 28, 2014
New measurements of atomic-scale magnetic behavior in iron-based superconductors by researchers at the Department of Energy's Oak Ridge National Laboratory and Vanderbilt University are challenging conventional wisdom about superconductivity and magnetism. The study published in Advanced Materials provides experimental evidence that local magnetic fluctuations can influence the performance o ... read more


ENERGY TECH
China Aims for the Moon, Plans to Bring Back Lunar Soil

Electric Sparks May Alter Evolution of Lunar Soil

China to test recoverable moon orbiter

China to send orbiter to moon and back

ENERGY TECH
Scientist uncovers red planet's climate history in unique meteorite

Opportunity Flash-Memory Reformat Planned

Memory Reformat Planned for Opportunity Mars Rover

A Salty, Martian Meteorite Offers Clues to Habitability

ENERGY TECH
US to Stop Using Soyuz Spacecraft, Invest in Domestic Private Space Industry

25 Years After Neptune: Reflections on Voyager

Long-term spaceflights challenged as harm to astronauts' health revealed

Voyager Map Details Neptune's Strange Moon Triton

ENERGY TECH
Same-beam VLBI Tech monitors Chang'E-3 movement on moon

China Sends Remote-Sensing Satellite into Orbit

More Tasks for China's Moon Mission

China's Circumlunar Spacecraft Unmasked

ENERGY TECH
NASA Awaits Boeing's Completion of Soyuz Replacement

Belka and Strelka, the canine cosmonauts

Russian Cosmonauts Conclude EVA Ahead of Schedule

Orbital cargo ship makes planned re-entry to Earth

ENERGY TECH
Sea Launch Takes Proactive Steps to Address Manifest Gap

SpaceX rocket explodes during test flight

Russian Cosmonauts Carry Out Science-Oriented Spacewalk Outside ISS

Optus 10 delivered to French Guiana for Ariane 5 Sept launch

ENERGY TECH
Orion Rocks! Pebble-Size Particles May Jump-Start Planet Formation

Rotation of Planets Influences Habitability

Planet-like object may have spent its youth as hot as a star

Young binary star system may form planets with weird and wild orbits

ENERGY TECH
Laser pulse turns glass into a metal

Researchers map quantum vortices inside superfluid helium nanodroplets

The power of salt

NASA Probes Studying Earth's Radiation Belts to Celebrate Two Year Anniversary




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.