Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nano 'pin art': NIST arrays are step toward mass production of nanowires

02.08.2010
NIST researchers grow nanowires made of semiconductors—gallium nitride alloys—by depositing atoms layer-by-layer on a silicon crystal under high vacuum. NIST has the unusual capability to produce these nanowires without using metal catalysts, thereby enhancing luminescence and reducing defects. NIST nanowires also have excellent mechanical quality factors.

The latest experiments, described in Advanced Functional Materials,* maintained the purity and defect-free crystal structure of NIST nanowires while controlling diameter and placement better than has been reported by other groups for catalyst-based nanowires. Precise control of diameter and placement is essential before nanowires can be widely used.

The key trick in the NIST technique is to grow the wires through precisely defined holes in a stencil-like mask covering the silicon wafer. The NIST nanowires were grown through openings in patterned silicon nitride masks. About 30,000 nanowires were grown per 76-millimeter-wide wafer. The technique controlled nanowire location almost perfectly. Wires grew uniformly through most openings and were absent on most of the mask surface.

Mask openings ranged from 300 to 1000 nanometers (nm) wide, in increments of 100 nm. In each opening of 300 nm or 400 nm, a single nanowire grew, with a well-formed hexagonal shape and a symmetrical tip with six facets. Larger openings produced more variable results. Openings of 400 nm to 900 nm yielded single-crystal nanowires with multifaceted tops. Structures grown in 1,000-nm openings appeared to be multiple wires stuck together. All nanowires grew to about 1,000 nm tall over three days.

NIST researchers analyzed micrographs to verify the uniformity of nanowire shape and size statistically. The analysis revealed nearly uniform areas of wires of the same diameter as well as nearly perfect hexagonal shapes.

Growing nanowires on silicon is one approach NIST researchers are exploring for making "nanowires on a chip" devices. Although the growth temperatures are too high—over 800 degrees Celsius—for silicon circuitry to tolerate, there may be ways to grow the nanowires first and then protect them during circuitry fabrication, lead author Kris Bertness says. The research was partially supported by the Defense Advanced Research Projects Agency (DARPA) Center on NanoscaleScience and Technology for Integrated Micro/Nano-Electromechanical Transducers (iMINT) at the University of Colorado at Boulder.

* K. A. Bertness, A. W. Sanders, D. M. Rourke, T. E. Harvey, A. Roshko, J.B. Schlager and N. A. Sanford. Controlled nucleation of GaN nanowires grown with molecular beam epitaxy. Advanced Functional Materials. Published online: July 13, 2010. DOI: 10.1002/adfm.201000381

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Materials Sciences:

nachricht ADIR Project: Lasers Recover Valuable Materials
21.07.2017 | Fraunhofer-Institut für Lasertechnik ILT

nachricht High-tech sensing illuminates concrete stress testing
20.07.2017 | University of Leeds

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>