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 Five developments for improved data exploitation
19.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI

nachricht Smart Manual Workstations Deliver More Flexible Production
04.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI

All articles from Information Technology >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>