Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Striped nanowires shrink electronics

07.02.2002


Multi-flavoured nanowires can act as miniature bar-codes, diodes and light sources
© SPL



Wires one-millionth of a millimetre wide change composition along their length.

Wires one-millionth of a millimetre wide that change chemical composition along their length, just as fruit pastilles change flavour along a packet, have been grown in the United States. These multi-flavoured nanowires can act as miniature bar-codes, diodes and light sources.

Conventional microelectronics components are etched into flat layers of semiconducting material. Charles Lieber and colleagues at Harvard University in Cambridge, Massachusetts, grow their wires - smaller than the thinnest wire on a commercial silicon chip - from vapours of the atomic ingredients.



Lieber’s group perfected their method for making semiconductor nanowires two years ago. They use a tiny blob of a catalyst, which stays at the growing tip of the wire like the point of a pencil tracing out a line. The size of the catalyst particle controls the wire’s width.

Now the researchers report that, by choosing their catalyst carefully - they use gold nanocrystals - they can grow sequential lengths of a single wire from different chemicals1. They use a laser to blast a semiconductor into a vapour, which then condenses into nanowires. Exposing the growing wires first to one kind of vapour and then to another varies the composition along the wire.

Superlattice lines up

The team has made wires about 20 nanometres across that contain alternating sections of the semiconductors gallium arsenide and gallium phosphide. Microelectronic engineers often use structures like this, called superlattices, in electronic devices. They are currently made by carving up flat sandwiches of layered semiconductors.

Superlattices are used, for example, as mirrors in microscopic lasers, or as waveguides to capture and confine light. If electrons are trapped in a thin layer of a semiconductor sandwiched between barriers of a different semiconductor, quantum wells are created that emit light. The colour of the light can be tuned by varying the well thickness.

Nanowire superlattices could be used in all these applications. Their size means that many more could be packed onto a single chip than today’s microelectronics components. The researchers envisage making nanowire lasers, for example.

Up the junction

To demonstrate the wires’ potential, Lieber’s group made structures called p-n junctions. They grew silicon nanowires in two sections, each spiced with a different additive to fine-tune the electrical behaviour of the silicon. These nanowire p-n junctions behave like diodes - they let current flow in only one direction.

The team also made p-n junctions that act as light-emitting diodes. Because these glowing devices are so small, the researchers hope to make them expel light one photon at a time. This could be useful in a new type of ultra-powerful information processing called quantum computing.

References

  1. Gudiksen, M. S., Lauhon, L. J., Wang, J., Smith, D. C. & Lieber, C. M. Growth of nanowire superlattice structures for nanoscale photonics and electronics. Nature, 415, 617 - 620, (2002).


PHILIP BALL | © Nature News Service
Further information:
http://www.nature.com/nsu/020204/020204-7.html

More articles from Information Technology:

nachricht Cutting edge research for the industries of tomorrow – DFKI and NICT expand cooperation
21.03.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI

nachricht Molecular motor-powered biocomputers
20.03.2017 | Technische Universität Dresden

All articles from Information Technology >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Big data approach to predict protein structure

27.03.2017 | Life Sciences

Parallel computation provides deeper insight into brain function

27.03.2017 | Life Sciences

Weather extremes: Humans likely influence giant airstreams

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>