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

PetLife Comments on CNN Story on Scorpion Venom Health Benefits August 27th, 2014

Nanodiamonds Are Forever: A UCSB professor’s research examines 13,000-year-old nanodiamonds from multiple locations across three continents August 27th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Chip Technology

Scientists craft atomically seamless, thinnest-possible semiconductor junctions August 26th, 2014

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Sensors

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Newly-Developed Nanobiosensor Quickly Diagnoses Cancer August 20th, 2014

Graphene rubber bands could stretch limits of current healthcare, new research finds August 19th, 2014

Nanoelectronics

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

Announcements

Nanodiamonds Are Forever: A UCSB professor’s research examines 13,000-year-old nanodiamonds from multiple locations across three continents August 27th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Malvern specialists to deliver inaugural short course on polymer characterization at Interplas 2014 August 27th, 2014

Photonics/Optics/Lasers

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Biomimetic photodetector 'sees' in color: Rice lab uses CMOS-compatible aluminum for on-chip color detection August 25th, 2014

Ultra-short pulse lasers & Positioning August 21st, 2014

Solar/Photovoltaic

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing August 11th, 2014

“Active” surfaces control what’s on them: Researchers develop treated surfaces that can actively control how fluids or particles move August 6th, 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