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."

Comments

Getting the Facts on Light Emitting Carbon Nanotub

[jscribner]

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.

Posted on physicsweb

[parkanoid]

Three days ago

Re:Mass Production (of nanotubes)

[wass]

yes, nanotech is currently one of the 'sexy' topics, and so every two months (or more often, usually) someone gets to publish their new fabrication or measurement technique.

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.