Scientists make world's smallest transistor

The Times of India ^ | MONDAY, SEPTEMBER 05, 2005 06:55:58 PM | The Press Trust of India

[CarrotAndStick]

SAN FRANCISCO: Two non-resident Indian scientists have created history by making the world's tiniest transistor entirely from carbon nanotubes.

Nanotubes are rolled up sheets of carbon atoms and are more than a thousand times thinner than human hair. The discovery heralds a new era of ultra miniature electronics where standard silicon transistors are replaced with much smaller versions fashioned from carbon nanotubes.

The new transistor is a Y-shaped nanotube with two branches that meet a central stem at a junction.

The current flowing from one branch to another can be switched on and off by applying a voltage to the third. Such binary logic called "gating" is the basis of nearly all transistors.

"The small size and dramatic switching behavior of these Y-shaped nanotubes makes them candidates for a new class of all-carbon transistor," says Prabhakar Bandaru, a materials scientist at the University of California, San Diego who led the team that included his colleagues Sungho Jin, graduate student Chiara Daraio and physicist Apparao M.Rao at Clemson University in South Carolina.

Their work published in the September issue of 'Nature Materials' has won instant acclaim from international science community. The demonstration of switches and logic devices made purely from Y-junctions puts nanotubes "at the forefront of next-generation electronics," Professor Hongqi Xu of the Nanometer Structure Consortium at Lund University in Sweden commented in the journal Nature.

Conventional transistors like those in Pentium chips are built from layers of semi conducting silicon but the chip size has already shrunk to a size that cannot get any smaller. The quest for ever smaller chips has driven scientists worldwide to explore nanotubes. They have already made logic circuits using nanotubes but these required metal 'gates' to control the flow of current.

Thus a true nanocircuit built entirely from nanotubes seemed like a dream until the pioneering work by Bandaru and colleagues. "The Y-junction based carbon nanotube transistor incorporates a gate as part of the structure and is fully self-contained," Bandaru told PTI.

"It is very novel as it dispenses with the need for an external gate." However, the US based Indians were not the first to make the Y-junction, however.

Four years ago renowned chemist C.N.R. Rao at the Jawaharlal Nehru Centre in Bangalore produced a Y-junction nanotube and even showed that it behaved like a diode allowing current flow in one direction but not the other.

"We have considerably extended the measurements (made by C.N.R. Rao's group) and made a practical transistor like device," Bandaru said.

The scientists made their Y-shaped nanotubes by adding a titanium-iron catalyst to a pot of straight nanotubes while they are growing. When a catalyst particle is trapped in a nanotube, the tube branches forming Y-junction.

"Y-junction nanotubes have been previously synthesized but not much work has gone into assembling them for practical devices," Bandaru said.

"Our group was one of the first to actually assemble them and experimentally demonstrate their switching and logic functionalities without the need for an external gate," he said.

Commercial applications are however still years away. Bandaru agrees that to make a working chip, engineers would need to assemble millions of evenly spaced, predictably shaped nanotube transistors. "Many smart people are working on this and the problem will likely be solved soon," he said.

One must remember that even for the Pentium chips that are used in our computers (which now have over 300 million transistors), the progenitor was a simple integrated circuit with two transistors in 1958, Bandaru pointed out.

"We are probably in the same stage with Y-junctions and the future looks good with so many possibilities." The researchers plan to experiment with various other catalyst particles in order to tailor the three-way gating properties of the Y-junctions. They are also trying to make T and X-shaped nanotubes that could allow different functions.

According to Bandaru one other novel feature of the transistor is that the catalyst particle at the Y-junction can be "nano-engineered" either during synthesis or by focused ion-beams. "This gives rise to a whole series of possibilities, including giving each Y-junction device its own character and switching properties."

Indian scientists may have missed the semiconductor revolution of the 1960's that heralded the era of computers based on silicon. But when the era of nanoelectronics dawns on the world scene they are surely to be in the driver's seat.

[Archidamus]

Two non-resident Indian scientists, otherwise known as Americans.

[fat city]

You mean they'll be able to make radios that can fit in your pocket?

[CarrotAndStick]

Maybe, like that HP ad which went on about making cell phones so that ants may be able to use them (what an idiotic suggestion!).

[adam_az]

"Two non-resident Indian scientists, otherwise known as Americans."

Sounds like theyre on student visas?

Is there a patent involved? Who owns it, them or UCSD?

[robertpaulsen]

"Indian scientists may have missed the semiconductor revolution of the 1960's ..."

Just as they are missing the nanoelectronics revolution.

Non-resident Indian scientists on the other hand ...

[freebilly]

"The small size and dramatic switching behavior of these Y-shaped nanotubes makes them candidates for a new class of all-carbon transistor," says Prabhakar Bandaru, a materials scientist at the University of California, San Diego who led the team that included his colleagues Sungho Jin, graduate student Chiara Daraio and physicist Apparao M.Rao at Clemson University in South Carolina.

All the engineers with Anglo surnames were too busy putting condoms on cucumbers in High School to be able to participate in anything this petty....

[FireTrack]

"You mean they'll be able to make radios that can fit in your pocket?"

And computer implants to supplement a brain.

[manwiththehands]

BORG ALERT PING

[LoneRangerMassachusetts]

All the engineers with Anglo surnames were too busy putting condoms on cucumbers in High School to be able to participate in anything this petty....

Engineering is hard work. You have to understand the laws of nature and logically create ways to harness them. Lazy Anglos on the other hand won't get their hands dirty with hard work. They become lawyers who twist laws in illogical ways to suit their purposes, especially to improve their fees.

[CarrotAndStick]

Vivek Paul?

[SedVictaCatoni]

Two non-resident Indian scientists, otherwise known as Americans.

This probably means that they are Indian nationals who are on temporary work or academic visas in the United States. Hence, they are not Americans, they are Indians who happen to be in America at the moment.

[CarrotAndStick]

Non-resident Indians are mostly citizens of India. Whether they have a dual citizenship is another matter.

http://en.wikipedia.org/wiki/NRI

A non-resident Indian (NRI) is an Indian citizen who has migrated to another country. Other terms with the same meaning are overseas Indian and expatriate Indian. For tax and other official purpose the government of India considers any Indian national away from India for more than 180 days in a year an NRI. In common usage, this often includes Indian born individuals who have taken the citizenship of other countries.

A Person of Indian Origin (PIO) is literally, simply a person of Indian origin who is not a citizen of India. For the purposes of issuing a PIO Card, the Indian government considers anyone of Indian origins up to four generations removed, to be a PIO [1].

There is a huge NRI and PIO population across the world, estimated at around 25 million.

[Landru]

"All the engineers with Anglo surnames were too busy putting condoms on cucumbers in High School to be able to participate in anything this petty..."

HA!!
True-true.

The nation's young generation of anglos have other forte's also, though.
Recycling, sensitivity and amazing insights into the musical legends of their times like 50 cent.

I really feel the upcoming generation needs a name all their own, & considering our [immediate] future?

..."The Good Hands People" is most fittin'.

[SedVictaCatoni]

All the engineers with Anglo surnames were too busy putting condoms on cucumbers in High School to be able to participate in anything this petty....

Or too busy at football or basketball practice. Good thing we still excel in the vital field of high school athletics. Beats learning calculus or something.

[TXnMA]

Lazy Anglos

Been wondering if you have racist leanings; thanks for the clarification...

FWIW, I was one of those "Lazy Anglos" who worked in Jack Kilby's (another "Lazy Anglo"?) R&D lab back when ICs had one gate per chip...

[Larry Lucido]

I hear they're making vacuum tubes really small, too.

[CarrotAndStick]

For the best audio quality, the pros still prefer tube amps.

http://www.audioadvisor.com/store/productdetail.asp?sku=MHSHANCD&loc=2

Analog Tube or Solid State Output The CD-T100 is the world's first vacuum tube HDCD player, and this technology is beautifully implemented. The analog circuitry is built around the 6N3P triode vacuum tube for both the line and headphone outputs. The tube circuitry gives this player a smooth, natural-sounding quality and the kind of warmth you can only achieve with tube electronics. Four separate metal shields are fitted to the analog / digital filter and tube power modules, ensuring quiet operation with detailed sound. To take advantage of the tube section, use the tube audio output jacks on the rear panel. If you prefer to use the Shanling's exceptional solid state analog section instead, just plug into the parallel RCA jacks instead. Finally, for access to the digital stream, a coaxial digital output is also included for use with additional outboard equipment.

Price: $1,795.00

[sittnick]

"The small size and dramatic switching behavior of these Y-shaped nanotubes makes them candidates for a new class of all-carbon transistor,"

That's nothing. Wait till you see what they do with "Y-shaped nano-tubed" capacitors!

[freebilly]

My son used to tutor some of the teammates on his football and baseball teams....