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Light-Producing Nanotubes Could Mean Faster Chips
CannibalBob writes "From PCWorld: Researchers at IBM have used carbon molecules to emit light, a breakthrough that could replace silicon as the foundation of chips and lead to faster computers and telecommunication equipment. This is the first time light has ever been generated from a molecule by applying electricity. Read the article."
Here's the detailed info on all this:
IBM Research Light Emitting Carbon Nanotube news release
There's also an animation, but the pictures in the release are easier to follow.
JS - IBM Metaverse devteam
The opinions expressed here are mine & not necessarily representative of IBM
a single molecule emits light whenever it makes a state transition... Its the phenomenon that caused the paradigm shift from classical to quantum mechanics.
That can't be the point.
How do light bulbs work? True, they burn as a side effect of being heated, but you apply electricity, and you [eventually] get light. Then there's the the whole laser thing... Florcent tubes?
Well, any light form needs energy - and electricity is a common way of providing this.
Light bulbs emit light because they are heated by electricity. Unfourtunately, about 95% of the light emitted is not visible to humans, and thus wasted (human eyes are tuned to best view light from a certain body at about 6000 degrees, and this is much hotter than the light bulb - thus the inefficiency).
There are, however, ways to convert electricity to light without heating anything. LEDs do this - all energy is converted to light of a single certain frequency - which we can see. This is true for lasers also, but they go even further by not only having light of a single frequency but also aligning the light waves that compose the light.
But both light bulbs and LEDs are made of big crystals of metal / silicon (as opposed to molecules). What is new here is the atomic structure of the of the light emitting material; it is nanotubes which technically are big molecules. This is a major discovery - although it is probably too early to tell exactly what it will be useful for in the future.
Tor
would constitute a single molecule. Applying electricity to it, as pointed out in the article, they were able to produce light (1.5 micron). An LED, tungsten wire, or burning lump of coal are not made up of a single molecule, no more so than an ice cube is a single molecule of water. What this constitutes is an engineering first. What is left to be seen is if they can find useful applications and mass produce it.
End of Line.
That would be from a SINGLE molecule; nanotubes are single molecules. More handy dandy info at IBMs nanonotube web site.
Roving Web-Teleoperated Robot
Yes, it is the point. Although it happens molecule by molecule when it happens in mass, there wasn't a way to control the applicatiion of a signal and stimulate emmision from a chosen molecule. Now there is. For the first time ever, *a* molecule is made to emit when electrically stimulated.
Three days ago
I'm a graduate physics student (experimentalist), and I'll be working with nanotubes. But we're just building up our lab now (my advisor just arrived here only a few months ago). We'll be doing measurements with carbon nanotubes, initially continuing what we did last summer (at her old postdoc lab) by measuring superconducting nanowires. If you're curious, these nanowires are created by sputtering a superconducting alloy (MoGe) on top of a nanotube substrate. They're interesting because the system dimensions are small enough that the wires are effectively one-dimensional, which means they can't support long-range order and thus cannot allow Cooper-pair supercurrents to flow unimpeded through the wire.
It's hard to create nanotubes, and harder to put them where you want them. One way to create them is to use chemical vapor deposition (CVD), where you basically try to create a controlled environment where some hydrocarbon (eg methane) is ignited (the environment is somewhat oxygen-deficient so CO2 isn't the only carbon species produced) The 'soot' that is subsequently deposited on your substrate should contain nanotubes if the right conditions are met.
To get the tubes in certain places, sometimes little 'seeds' of iron particles are used, in hopes the nanotubes will grow/branch from them. It's hard to create good SWNT (Single-Walled Nanotubes), but easier to form 'ropes' of many nanotubes intertwined together.
Another difficult factor to control is the 'chirality' of the tube. Basically, a carbon nanotube is a rolled graphite sheet, but when the sheet is rolled, it can have certain 'twist' to it. For example, if you rolled lined paper into a cylinder, you can have zero helicity, in which case your lines will form independent circles. Or you can shift the lines by an integer number, in which case the lines will form helices of varying pitch. This factor in nanotubes determines the electronic band structure, which mandates whether the tubes are metallic or semiconducting. It would be highly desirable to be able to produce consistently tubes of the same chirality.
I hope this makes sense, I was up all night doing E&M homework (ya gotta love Jackson), so my brain is kinda fried right now.
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