Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Nanowires for the electronics and optoelectronics of the future

Under the scanning electron microscope (SEM): palladium octaethyl-porphyrin nano-lamellae and nanowires growing on a perylene nanowire which has been sputtered with silver particles.
Under the scanning electron microscope (SEM): palladium octaethyl-porphyrin nano-lamellae and nanowires growing on a perylene nanowire which has been sputtered with silver particles.

Abstract:
Process for manufacturing nanoelectronic "mini-circuits" developed

Nanowires for the electronics and optoelectronics of the future

Switzerland | Posted on June 24th, 2010

The tale begins with a feasibility study on the manufacture of colored fluorescing thin films for optical safety applications. An EU project on the development of novel gas sensors followed. In the meantime, Empa researchers have successfully synthesized complex organic nanowires and managed to attach them together with electrically conducting links - the first step towards the future production of electronic and optoelectronic components.

Organic semiconductors are very promising candidates as starting materials for the manufacture of cheap, large area and flexible electronic components such as transistors, diodes and sensors on a scale ranging from micro to nano. A condition for success in achieving this goal is the ability to join components together with electrically conducting links - in other words, to create an electronic circuit. Empa scientists have developed a new method which allows them to create simple networks of organic nanowires.

The origin: an EU project called «PHODYE»

When Spanish physicist Angel Barranco returned to Valencia after a three year research stint at Empa, he initiated the EU project «PHODYE» with, among others, his old Empa colleagues. The aim is to develop highly sensitive gas sensors, for monitoring road vehicle emissions, for example, or for providing laboratory staff and mine workers with an early warning of the presence of poisonous substances. The sensors are based on fluorescing thin films which change color and fluoresce on contact with certain gas molecules.

"We were thinking in terms of a sort of electronic key for security applications, which would only react to certain optical conditions," explains Empa physicist Pierangelo Groening. Necessary for this are transparent, strongly fluorescing thin films, so Groening and Barranco developed a plasma-deposition process in order to store fluorescing dye molecules such as metallo-proyphins, perylenes and phthalocyanines unmodified and at high concentrations in SiO2 or TiO2 layers.

It soon became apparent that if certain gas molecules deposited on dye particles in the thin films, then these fluoresced at different wavelengths and the thin film changed color as a result. If different dyes are used then the gases which are toxic to humans can be detected at very low concentrations.

A surprisingly wide range of uses

However, for many sensor applications it is important that the response time be as short as possible, something which is hardly possible with compact plasma dye layers. It is, on the other hand, possible with layers which have very a porous structure, resembling the nap of a nanometer-scale carpet. Scientists hope to derive further benefits from such layers because they increase the area onto which the gas molecules to be detected can adsorb, and also shorten the diffusion distances, allowing the sensor to respond faster. Physicist Ana Borras thereupon developed a new vacuum deposition process for synthesizing organic nanowires.

In the meantime the Empa researchers made progress, learning how to manufacture nanowires with very widely varying characteristics by appropriately selecting the starting molecule and the experimental conditions. Nanowires of metallo-phthalocyanine molecules have diameters of a mere 10 to 50 nanometers and a length of up to 100 microns. What is unusual and unexpected about the new method is that by exactly controlling the substrate temperature, molecule flow and substrate treatment, the organic nanowires develop a previously unattained, perfectly monocrystalline structure.

Immediately after the first studies were made with the electron microscope it was clear to Groening that the new process could not only provide nanowires for the gas sensors but also make it possible to create complex "nanowire electric circuits" for electronic and optoelectronic applications such as solar cells, transistors and diodes. This is because the different types of nanowires can be combined as required to form networks with widely varying properties, as Groening and coworkers report in the scientific journal Advanced Materials and elsewhere.

The trick to achieving this lies in a second step in which the nanowires growing on the surface are "decorated" with silver nanoparticles by a sputter-coating process. A target, in this case a piece of solid silver, is bombarded with energetic ions, knocking off silver atoms which enter the gas phase and are deposited onto the nanowires. In a final step, the Empa team now grow more nanowires which, thanks to the silver particles, are in electrical contact with the original wires - the basis of an electrical circuit on the nanometer scale.

The first step from microelectronics to nanoelectronics

The first electrical conductivity measurements, made with the help of a four-tip scanning tunnel microscope in ultra high vacuum, exceeded the most optimistic expectations - the material is of an unusually high quality. "This opens up the possibility of soon being able to manufacture organic semiconductor materials," says Groening confidently. "And that, too, using a simple and economic process." In the meantime the researchers have successfully synthesized increasingly more complex structures of nanowires, and managed to link these together using a good deal of skill and a sure touch.

Take, for example, nanowires consisting of sections made with different starting molecules. If these molecules can transport either only positive or only negative charges, then a diode is created which allows current to flow in one direction alone. Groening speculates that it is quite possible that one day components for nanolectronics and nanophotonics will be made using this technique.

Reference
A. Borras, O. Groening, J. Koeble, P. Groening: Organic Nanowires: Connecting Organic Nanowires, Advanced Materials, vol. 21, issue 47, pp. 4816 - 4819; DOI: 10.1002/adma.200901724

####

About Empa
Empa is an interdisciplinary research and services institution for material sciences and technology development within the ETH Domain. Empa’s research and development activities are oriented to meeting the requirements of industry and the needs of our society, and link together applications-oriented research and the practical implementation of new ideas, science and industry, and science and society.

For more information, please click here

Contacts:
Dr. Pierangelo Gröning
Empa,
Tel. +41 44 823 40 04
+41 33 228 52 15


Editor / Media contact
Dr. Michael Hagmann
Empa, Communication Dept.
Tel. +41 44 823 45 92

Copyright © Empa

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Haydale Secures Exclusive Development and Supply Agreement with Tantec A/S: New reactors to be built and commissioned by Tantec A/S represent another step forward towards the commercialisation of graphene October 24th, 2014

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Nanoparticle technology triples the production of biogas October 23rd, 2014

Chip Technology

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

NIST offers electronics industry 2 ways to snoop on self-organizing molecules October 22nd, 2014

Materials for the next generation of electronics and photovoltaics: MacArthur Fellow develops new uses for carbon nanotubes October 21st, 2014

Sensors

MEMS & Sensors Technology Showcase: Finalists Announced for MEMS Executive Congress US 2014 October 23rd, 2014

Journal Nanotechnology Progress International (JONPI), 2014, Volume 5, Issue 1, pp 1-24 October 22nd, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Graphenea opens US branch October 16th, 2014

Nanoelectronics

NIST offers electronics industry 2 ways to snoop on self-organizing molecules October 22nd, 2014

Materials for the next generation of electronics and photovoltaics: MacArthur Fellow develops new uses for carbon nanotubes October 21st, 2014

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Announcements

Haydale Secures Exclusive Development and Supply Agreement with Tantec A/S: New reactors to be built and commissioned by Tantec A/S represent another step forward towards the commercialisation of graphene October 24th, 2014

QuantumWise guides the semiconductor industry towards the atomic scale October 24th, 2014

Advancing thin film research with nanostructured AZO: Innovnano’s unique and cost-effective AZO sputtering targets for the production of transparent conducting oxides October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Photonics/Optics/Lasers

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

New VDMA Association "Electronics, Micro and Nano Technologies" founded: Inaugural Meeting in Frankfurt/Main, Germany October 15th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 2014

Solar/Photovoltaic

Advancing thin film research with nanostructured AZO: Innovnano’s unique and cost-effective AZO sputtering targets for the production of transparent conducting oxides October 23rd, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

Dyesol Signs Letter of Intent with Tata Steel October 13th, 2014

DNA nano-foundries cast custom-shaped metal nanoparticles: DNA's programmable assembly is leveraged to form precise 3D nanomaterials for disease detection, environmental testing, electronics and beyond October 10th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE