Breakthrough will help embed electronics on plastic sheets

Tag : Metal Sheets

Washington, July 24 (IANS) A breakthrough in fabricatingtransistors from carbon nanotube networks will take electronics astep closer to being embedded on plastic sheets.

The advance is likely to permit researchers to use thesespecialised transistors to create high-performance,shock-resistant, lightweight and flexible integrated circuits atlow cost.
Possible applications include an electronic skin that covers anaircraft and automatically monitors the formation of cracks toalert technicians and prevent catastrophic failures.
Its key advantage is that it can be produced at low temperatures,enabling the transistors to be placed on flexible plastic sheetsthat would melt under the high temperatures required to manufacturesilicon-based transistors, he said.
Such shape-conforming electronics are not possible usingconventional silicon-based circuits, which are manufactured onrigid wafers or glass plates.
The nanonets are made of tiny semiconducting cylinders calledsingle walled carbon nanotubes. But they have been plagued by acritical flaw. Metallic nanotubes form unavoidably during theprocess of making carbon nanotubes.
These metal tubes then link together in meandering threads thateventually stretch across the width of the transistor, causing ashort circuit.
The breakthrough solves this problem by cutting the nanonet intostrips, preventing short circuits by breaking the path of metallicnanotubes.
“This is a fundamental advance in how nanotube circuits aremade,” said Ashraf Alam, a professor of electrical andcomputer engineering at Purdue University.
He is working with Kaushik Roy, also a professor of electrical andcomputer engineering, and doctoral students Ninad Pimparkar andJaydeep P. Kulkarni.
Researchers at the University of Illinois led experimental labresearch to build the circuits, and Purdue led research to developand use simulations and mathematical models needed to design thecircuits and to interpret and analyse data.
“These findings represent the culmination of four years ofcollaborative efforts between the Illinois and Purduegroups,” Rogers said. “The work established thefundamental scientific knowledge that led to this particularbreakthrough and the ability to make circuits.”
“Other researchers have proposed eliminating the metallicnanotubes,” John A. Rogers, professor of chemistry, said.“Instead, we found a very nice way of essentially removingthe effect of these metallic nanotubes without actually eliminatingthem.”
The researchers created a flexible circuit containing more than 100transistors, the largest nanonet ever produced and the firstdemonstration of a working nanonet circuit, Alam said.
These findings were published Thursday in Nature.