Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanowires can now be controlled

23.12.2008
Nanoscience researchers at Lund University in Sweden have shown that they can control the growth and crystal structure of nanowires down to the single atom level.

How this can be done is described in an article to appear in the January issue of Nature Nanotechnology, with Philippe Caroff and Kimberly Dick as the main authors.

According to Professor Lars Samuelson, this is a breakthrough both in the development of nanowire growth, and in the understanding of the fundamental materials physics processes involved.

- The results achieved here establish our position in this area of science and technology and give our ambitions an increased credibility, he says. The useful applications will not be far away.

It has been known for a long time that most semiconductor materials used in nanowires, including the very interesting material Indium Arsenide (InAs) studied here, are affected by irregularities in the layer-by-layer stacking sequence. These affect the electronic and optical properties in uncontrolled ways, and are therefore undesirable.

But now Philippe Caroff and Kimberly Dick have shown that it is possible to control these variations in great detail, which can be used for the development of new functions in nanowires.

It is now possible not only to fabricate perfect, defect-free nanowires, but also to switch freely between different crystal types along the length of a single nanowire, to produce a, so-called, superlattice, but still using only one chemical compound (InAs).

- Two of the key parameters needed to control the crystal structure are nanowire diameter and the temperature at which they are fabricated. But there are in total at least 10-12 different parameters that must be controlled when producing the nanowires, says Kimberly Dick.

Although this result has been demonstrated primarily for the binary compound InAs, it is believed that the mechanisms controlling the nanowire structure can be generally applied to related semiconductor materials used in nanotechnology.

With this technique it is also possible to grow highly regular nanowires with a perfect periodic facetted character.

Electron microscopy images show that the arrangement of atoms in the nanowire crystal exactly matches theoretical simulations. The electronic and optical properties of these wires have not been investigated yet but will be in the focus of theoretical as well as experimental studies.

The nanowires in this study had a typical diameter of 10-100 nanometers (one nanometer is one-millionth of one millimeter) and length of a few micrometers (one-thousandth of one millimeter).

The wires are produced by "baking" in an oven with a supply material in gas form, and grow from small microscopic gold "seeds". Kimberly Dick defended a PhD thesis last year containing many electron microscopy images of similar nanowires.

The researchers work within the Nanometer Structure Consortium (nmC) at Lund University to also find commercial applications for these nanowires in electronics and opto-electronics, such as for light-emission and solar cell applications.

Lars Samuelsson could be contacted at
e-mail: Lars.Samuelson@ftf.lth.se or +46-70 317 7679.
Pressofficer Mats Nygren Mats.Nygren@kansli.lth.se or +46-708 220187
The original article "Controlled polytypic and twin-plane superlattices in III-V nanowires" written by the Lund University scientists P Caroff, K A Dick, J Johansson, M E Messing, K Deppert and L Samuelson is available at www.nature.com/naturenanotechnology.

It is also reviewed in an article in Semiconductor Today: www.semiconductor-today.com/news_items/2008/DEC/LUNDUNIVERSITY_021208.htm

Mats Nygren | idw
Further information:
http://www.vr.se
http://www.lth.se/formedia/nanofigurer/
http://www.semiconductor-today.com/news_items/2008/DEC/LUNDUNIVERSITY_021208.htm

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>