Posted on 05/27/2006 6:17:55 PM PDT by PeaceBeWithYou
Researchers at IBM have overcome an important obstacle to building computers based on carbon nanotubes, by developing a way to selectively arrange transistors that were made using the carbon molecules. The achievement, described in the current issue of Nano Letters, could help make large-scale integrated circuits built out of carbon nanotubes possible, leading to ultrafast, low-power processors.
For decades, the size of silicon-based transistors has decreased steadily while their performance has improved. As the devices approach their physical limits, though, researchers have started looking to less conventional structures and materials. Single-walled carbon nanotubes are one prominent candidate -- already researchers have built carbon nanotube transistors that show promising performance (see The Nanotube Computer). According to estimates, carbon nanotubes have the potential to produce transistors that run 10 times faster than even anticipated future generations of silicon-based devices, while at the same time using less power.
But so far research in the field has hit a roadblock: not being able to control the placement of nanotube transistors, making it impossible to build complex integrated circuits. "The way most [nanotubes transistors] are made now, nanotubes are randomly dispersed on a surface in solution, then source and drain contacts are randomly printed using lithography, and then you search around until you find by chance a tube that goes between a source and a drain," says James Hannon, one of the researchers involved with the work at IBM's T.J. Watson Research Center in Yorktown Heights, NY.
To gain control over the arrangement of transistors, the IBM researchers coated the nanotubes with molecules that bind only to patterns of metal oxide lines on a surface, and not to the areas in-between.
To make working transistors, the researchers laid down lines of aluminum using a lithography technique. These wires serve as the gates that turn the transistors on and off. They then oxidized the aluminum to form a thin aluminum oxide layer on top of the wires, which acts as both a dielectric and the material to which the nanotubes will bind. After applying carbon nanotubes in solution and allowing them to bind to the aluminum oxide, the researchers deposited palladium leads perpendicular to the aluminum/aluminum oxide wires. These leads crossed over the nanotubes, becoming the source and drain of the transistor.
While developing this method of organizing nanotube transistors is an important step, much work remains to be done before commercial processors will be available. For one thing, exploiting the full potential of nanotube transistors will require improving the leads, possibly by using nanotubes in place of the palladium wires.
But perhaps a more pressing problem is finding reliable and inexpensive ways to isolate different types of carbon nanotubes. Current fabrication techniques produce a mix of nanotubes with different sizes and electronic properties, not all of which will work well in integrated circuits.
Because of these challenges, the first applications of carbon nanotube transistors will probably not be as high-performance processors, Hannon says, but highly sensitive sensors that work even with a mix of different nanotubes.
Meanwhile, others are developing devices that don't rely on nanotubes' high-end electrical properties, but rather on features such as their strength and flexibility. This skirts the need both to sort and to individually arrange the nanotubes. The Woburn, MA-based company Nantero, for example, takes advantage of nanotubes' strength and flexibility to make memory devices. "We use [nanotubes] as electromechanical devices, so we just bend them up and down to represent zeros and ones," says Nantero CEO Greg Schmergel. In this application, clusters of nanotubes rather than single tubes can be used, so they can be patterned using lithography.
Eventually, Schmergel says, nanotubes could replace every part of semiconductor devices by using all of the tubes' features. "Nanotubes have quite a number of unique properties all combined in one material. They can replace memory, logic, the interconnect, ultimately they can replace everything in the chip, so it definitely makes sense to pursue all of those angles," he says.
Selectively placing carbon nanotubes (thin green line in inset enlargement) for transistors could lead to ultrafast, low-power computers. In the larger image, the vertical line is an aluminum oxide wire and horizontal lines are sources and drains. (Courtesy of IBM.)
Because computing power is a lot like knowledge, we will never have enough or satisfy the demand for it. These new chip architectures will allow new forms of computing devices as well as a host of new applications. Defense, aerospace, medicine, communications, consumer electronics, etc....
If you can create the processing power then someone will create the application needed to run on it.
There's a LOT of work going on in photonics right now. Quantum entanglement at greater than c(DeBroglie's matter wave crest speed - U=c^2/v), "slow" light(down to 37 mph), fiber optics, materials that change index of refraction in picoseconds, and of course photons are 1000 times faster than electrons. Thus it just seems logical that light will be the basis for a whole new type of computer vastly superior to poky dit-dah-dit binary-electron computers.....Yes, you still need to solve read/write/memory/operations problems but think of it : 256 distinguishable colors, 500 pixels/line, 500 lines = a very BIG number. If you can distinguish a MILLION wavelengths(+ intensities + poarizations, say)and high definition TV, you can write a number(representing data/info)so LARGE that it would be like a football field of grass, and you'd spend your life human-eye-reading a single blade of grass. What is 3^4^5^6^7^8^9^10^11? And that's just for starters...add sounds(frequencies, intensities)odors...hey, it could even beat me and deep blue at chess.
There are no applications that need more processing power except human to machine direct interface and more human like robots.
I do not want to go there.
Machines are supposed to serve man, not to combine with or replace man.
Yes, fascinating...and interesting. Here we are, developing what you could call "alien technology", QM/nanotech/incredible computers/AI/AG, etc, etc; but we're still primitive savages, "apes with guns" is how they refer to us. Thus there must be a growing up/shocking experience like WW III/armageddon seared into human consciousness so that we will be MATURE and SELF DISCIPLINED enough to control the VAST new powers that science is giving us. Witness Iran and kooks with nucs..... Again, you don't leave a loaded gun in a nursery for children to play with. You don't let 5 year olds drive semitrucks on the freeway.....And now you understand why these amazing new energy discoveries that we already know about, that would get rid of oil-dependence, have to be kept OFF the market. Just look at trash-lined highways....
More meat to stune all beebers
If we're merely average, we're already ahead of half of them.
Someone on FR recently quoted Prof. Niklaus Wirth (inventor of Pascal, Modula 2 and Oberon) as saying, "Software is getting slower faster than hardware is getting faster."
The Fermi Paradox : if the universe has zillions of inhabited planets(the Drake Equation = SETI)how come we don't hear them on radio wavelengths? We've been sending out radio/TV/microwave for almost a century now, an expanding spherical wavefront 100 lightyears in radius, and yet we hear NOTHING, how come? Is it a "local-yokel" problem, or is there a deeper reason?
Nowhere Man will one day be SOMEBODY MAN, faith and patience my friend, faith and patience. As to Atlantis/unicorns and such : "atlantis" is a third hand account of a village in western greece on the shore of the gulf of corinth that was earthquake-shaken and subsequently sank into the ground via liquifaction(there are pictures of exactly this happening in japan); the subsidence was so extreme that a new bay was created, that covered this "atlantis" village. Then as the centuries passed the river that fed into that bay built up a silt layer and filled it to level land again. Archeologists have already dug to and recovered artifacts from that village. So much for "atlantis".....Unicorns : early greeks were EXPLORERS ranging far and wide. One explorer returns from africa with a description of a RHINOCEROUS, a horse with one horn on its head, thus fantasized into the "unicorn" by the greek dreamers.....Thus you have to consider the limited travel, knowledge, literacy of past ages; then apply Occam's Razor to most myths.....As to cancer, yes, the medical community is a vast vested interest; SOLVING the cancer problem means they are OUT of business in that area. I'm a shriner and we have 22 FREE hospitals in North America for crippled and burned children, and yet only 40% occupancy. Your usual medico will almost NEVER mention us because there goes $250,000 to $500,000 out the door with each child(family)gone to a shrine hospital....As to drug addiction : another vested interest(cops/courts/prisons). If you developed a dopamine drug vial, like an old fashioned hearing aid clipped on the ear, that fed dopamine(other brain chemicals)directly into the brain; cocaine, heroin, meth, etc would go away; and with it a LOT of business for this vested interest. As a medical device each unit would be specific to that person with a prescription. You see, dopamine(other brain chemicals)are energy-intensive for the body to make, so if you self-inject them(to get "happy")that's fine with your body(which doesn't have to make them). Simple solutions, only VESTED INTERESTS stand in the way.
You're the first person, including my EE professors, who has offered a plausible explanation; thanks!
Hey, how's it going?
My kids, ages 1 and 3, still use my 23-year-old Apple IIe to learn . Old, slow, limited... and reliable.
My RAID-drive 2.2Ghz 512MB Athlon was recently compromised by a virus which actually destroyed the CPU! That's right - After a full reinstallation of Windows, the only way it will operate is with the CPU cache (Level 1?) turned OFF. Of course, it takes about 15 minutes just to boot. I had a backup, non-RAID drive which was also compromised. IOW, it's a worthless piece of sh!t.
Hi; Well, spending a rainy, cold memorial weekend inside finishing my big SATUJT helicopter model, too miserable outside to work on construction project(sheetrock). See RCTOYS - dragan flyer II RC model, and aerosafe eagle, that's the basic idea. I add : central spherical cabin w/Transfer Ring between cabin and outer plate(containing 4 rotors)with hinge-pins at 0 deg and 180 deg(C to TR)and 2 more at 90 deg and 270 deg(TR to OP)for U JoinT action. Cabin stays vertical but TR/OP rotate any-which-a-way around it. Figured out this SATurnUJoinT idea 7-8 years ago, designing a possible LOGGING helicopter(went thru 8 iterations to arrive at basically the same idea as DF II and aerosafe eagle concepts).....Next model : edge spinning paddle wheels on a "brick" shape, your basic semitruck/UPS van. As you may know, a "brick" has 14 times the aerodynamic drag as a fish/torpedo but square box is most efficient shape to pack/move square boxes. Thus the aero-shells on cabs approximating that ideal fish shape. So, 4 long-thin spinning paddle wheels(or old lawnmower curved blades)on front 4 edges(actually 3 on semitruck because of undercarriage)that actively PULL air off the front plate and another 4(actually 3)on the back edges that PILE up air on the back doors. Thus reversing normal C-T aerodynamic drag to T-C PUSH YOU/PULL ME thrust. Since only about 10% of diesel energy goes to "snow-plowing" air out of the way(the rest is WASTE HEAT)and pulling it forward(tensile stress on rear doors is why dust collects on them)the energy to roll a semitruck down the freeway at 70 mph should drop proportionately. My main problem will be getting the 3V mini-motors centered/aligned with the 8 vidal sassoon paddle wheel brushes.....Got a call from my Senator's office last week, possibility of my plasma film-belt concept being developed in coal burning MHD. Coal slag(crud)builds up on throat walls, this solves the problem, making 60% efficient coal-to-electricity possible. It was a quickie/prelim idea I had 5 years ago sitting on waikiki beach. We'll see....
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