Nanotubes shed new light on fibre optics

Daily Newsletters

Sign up to ZDNet UK's daily newsletter.

NEWS
Researchers at IBM and the University of Toronto are squeezing light out of molecules. Scientists at IBM Research have discovered a new way to get carbon nanotubes to emit light, a breakthrough that might one day lead to advances in fibre-optic technology. At the University of Toronto, meanwhile, researchers have managed to produce light by injecting electrons into a polymer embedded with "quantum dots," microscopic crystals made of lead sulfide. Polymers -- chemicals made of large molecules in repeated structural units -- are being used in research into processor, display and other technologies. Carbon nanotubes -- long, thin strands of specialised carbon molecules -- and to a lesser degree nanocrystals, have become scientific celebrities in recent years because of their unusual electrical, thermal and mechanical properties. Both have emerged as candidates to replace silicon and metal in chip manufacturing a decade or two down the road. In the more immediate future, nanotubes could be employed to create corrosion-resistant paint or to improve fuel cells or batteries. The research from the two institutions essentially points the way toward another potential application: generating light. Generating light is not easy or cheap. Current optical equipment does the job, but optical components are difficult to manufacture and as a result expensive. By contrast, semiconductors can be mass-produced cheaply. Unfortunately, researchers have tried, and failed, to get silicon to generate light effectively. Several companies are currently trying to find ways to combine optical and silicon technologies. One method, called optoelectronics, involves converting optical signals into electrical signals, which can then be sent through inexpensive silicon. Other techniques involve embedding optical channels into silicon chips to route data faster and reduce energy consumption. "Our work represents a step towards the integration of many fibre-optic communications devices on one chip," Ted Sargent, the Nortel Networks Canada Research Chair in Emerging Technologies in the University of Toronto's electrical and computer engineering department, said in a statement. "With this light source combined with fast electronic transistors, light modulators, light guides and detectors, the optical chip is in view." Besides its potential use in chips, fibre-optic technology also is already used for transmitting information across long-distance telephone lines and in other networks. It carries more information than traditional copper wires, but it's also more expensive and difficult to install. "The commerical applications will be far away, but definitely this has a potential for great applications" for bridging the optical and electrical fields in communications equipment, David Tomanek, a professor of physics at Michigan State, said of the IBM results. Tomanek is also currently performing nanotube research with NEC. "Japan is very interested in optoelectronics," he added. "The more near-term application for optical is probably for sensors," said Josh Wolfe, a managing partner at Lux Capital, a venture firm concentrating on nanotechnology. Like everyone else, Wolfe cautioned that commercial applications remain a long way off, but said that researchers are making fairly impressive progress in characterising the properties of nanotubes. Let there be light In IBM's research, the light appears when a negative charge is applied to one end of the nanotube and a positive charge to the other. Light is created in this manner now in fibre-optic equipment, but the components have to be "doped," or chemically coated, so that the opposing charges will meet. By contrast, nanotubes are so small -- measuring about a nanometre, or a billionth of a metre, in diameter -- that they are considered one-dimensional objects. No doping is required. "When electrons and holes (positive charges) come together, they neutralise each other and become light," said Phaedon Avouris, manager of nanoscale science and technology at IBM Research. "A nanotube is the ultimate in confinement. If you place the electrons in one side and the holes on another, they will find each other." The light emitted by the nanotubes featured a wavelength of 1.5 microns, the same wavelength used in fibre optics today, noted Avouris. That means arrays of light-generating nanotubes have the potential to be used inside fibre-optic cables to transmit data. The University of Toronto prototype works in a similar fashion. Nanocrystals measuring about 5 nanometres wide sit in deep depressions (relatively speaking) in a polymer sheet. When electrons enter the polymer, they fall into the depressions and create light at wavelengths ranging from 1.3 microns to 1.6 microns, or millionths of a metre. Last year, researchers at Rice University showed how nanotubes can emit light. In Rice's experiments, the nanotubes were suspended in a liquid irradiated with a laser. In other words, the nanotubes were re-emitting externally created light. The results at Rice (which actually makes the nanotubes IBM uses in its experiments) were an important step, Avouris said. Further details on IBM's research results will come out in an edition of the journal Science on Friday. The University of Toronto published its work in the journal Applied Physics Letters. While commercialisation remains to be seen, the results show the potential versatility of nanotechnology. "The whole thing is science at this point. We are evaluating how far things can go," Avouris said about carbon nanotubes. "(But) so far, everything is working perfectly." Other nanotechnology research areas under way at IBM include developing new ways to manufacture carbon nanotubes and creating dense storage devices.
See the Hardware News Section for the latest update on everything from MP3 players and PDAs to supercomputing. Let the editors know what you think in the Mailroom.

Post your comment

In order to post a comment you need to be registered and logged in.

You can also log in with Facebook. Log in or create your ZDNet UK account below

  • Login

Will not be displayed with your comment

By signing up for this service, you indicate that you agree to our Terms and Conditions and have read and understood our Privacy Policy. Questions about membership? Find the answers in the Community FAQ

Get ZDNet UK's daily newsletter

Enter your email address to sign up

ZDNet UK Live

Moley

@GrueMaster. I prefer horses for courses rather than one size fits all. I, and I suspect most other computer users, do not really wish to have...

1 hour ago by Moley on A tale of two distros: Ubuntu and Linux Mint
greycynic

The product that scares me every time I have to use it is the Office 2007 version of Excel. The first bug that I found was applying the median...

1 hour ago by greycynic on Ten flawed products that derail productivity
GrueMaster

Nice review and very informative. One thing I'd like to add (in reply to whs001's 1st question), the main reason to have the same interface from...

2 hours ago by GrueMaster on A tale of two distros: Ubuntu and Linux Mint
Frederick Wrigley

I'be been using Mint 12 since the RC came out, and I am far more happy with the Cinnamon, the Mate, and, yes (with extensions), theGnome 3...

3 hours ago by Frederick Wrigley via Facebook on A tale of two distros: Ubuntu and Linux Mint
bdantas

Excellent article. One small correction, though--although a fresh installation of Linux Mint 12 will, indeed, provide the user with a version of...

4 hours ago by bdantas on A tale of two distros: Ubuntu and Linux Mint
Alan Ralph

In related news, the ISPs club together to get the members of the Home Affairs Select Committee (ya goofed on that part, ZDNet UK) copies of "The...

4 hours ago by Alan Ralph via Facebook on MPs urge ISPs to take down terrorist material
Alan Ralph

In related news, the ISPs club together to get the members of the Home Affairs Select Committee (ya goofed on that part, ZDNet UK) copies of "The...

5 hours ago by Alan Ralph via Facebook on MPs urge ISPs to take down terrorist material
Moley

For Gnome 2 die-hards, it is possible to add icons to the bottom panel (or top top panel, if you prefer) which provide the exact Gnome 2...

5 hours ago by Moley on A tale of two distros: Ubuntu and Linux Mint
ramwellian

Your comments would seem pretty naive and immature. Your 'solution' appears to be, "gee, let's all just give in to the hackers and give them...

6 hours ago by ramwellian on Cloud computing security: no more oxymoron?
BugStalker

"Interesting thought ... If you installed Win7 as a dual boot on a machine that previously only had Linux, and it wrecked your Linux installation,...

6 hours ago by BugStalker on Windows 7 Declares War on GRUB
whs001

This is an excellent summary of Ubuntu and Mint and the interface differences between them. Most such articles take a very partisan position for...

6 hours ago by whs001 on A tale of two distros: Ubuntu and Linux Mint
Moley

@ewallace. Not so clear. Anyone can obtain the text, for example from here http://www.ustr.gov/webfm_send/2379. I support ACTA so long as it and...

6 hours ago by Moley on ACTA: Facts, misconceptions and questions
45283

I think WinRT is fantastic. I just wish it was an option for people that didn't want to go through Microsoft's App Store with its attendant...

9 hours ago by 45283 on Why Windows 8 needs architectural hygiene for WOA
Burn-IT

Nine people? £30m? Who's back pocket is that lot going in? And IF they say it is for new buildings, what about all the ones the government has...

10 hours ago by Burn-IT on Police set to launch three £30m e-crime hubs
ewallace

Just to be clear, nobody knows what is in the text of ACTA, here is a photograph of the text of ACTA http://twitpic.com/8h9iju as submitted to the...

10 hours ago by ewallace on ACTA: Facts, misconceptions and questions
fgvrg56

Unfortunately main issue is that ASUS is refusing to accept that they make some mistake on this version of asus Transformer prime. 1 - GPS sensor...

12 hours ago by fgvrg56 on Asus Eee Pad Transformer Prime Wi-Fi & GPS problems?
Ben Woods

@Marcus A fair question. Just talked with Archos which said it was working on an announcement for next week....

13 hours ago by Ben Woods on Archos confirms G9 Ice Cream Sandwich update schedule
Marcus Karlsson

Any update on this, considering the claimed "first week of February"?

14 hours ago by Marcus Karlsson via Facebook on Archos confirms G9 Ice Cream Sandwich update schedule
apexwm

Bill Goodrich : Just as al_langevin pointed out, with Windows Server 2008 there is no Services for Macintosh anymore. It's gone, not available....

22 hours ago by apexwm on Windows Server 2008 drops the ball for Mac compatibility
txtrainguy

Replying to an old topic that I'm currently facing with my CEO (who is on a Mac). Our servers are primarily Windows Servers, office is about...

1 day ago by txtrainguy on Windows Server 2008 drops the ball for Mac compatibility