One of the world's smallest electronic circuits created

A team of scientists, led by Guillaume Gervais from McGill's Physics Department and Mike Lilly from Sandia National Laboratories, has engineered one of the world's smallest electronic circuits. It is formed by two wires separated by only about 150 atoms or 15 nanometers (nm). This discovery, published in the journal Nature Nanotechnology, could have a significant effect on the speed and power of the ever smaller integrated circuits of the future in everything from smartphones to desktop computers, televisions and GPS systems.

This is the first time that anyone has studied how the wires in an electronic circuit interact with one another when packed so tightly together. Surprisingly, the authors found that the effect of one wire on the other can be either positive or negative. This means that a current in one wire can produce a current in the other one that is either in the same or the opposite direction. This discovery, based on the principles of quantum physics, suggests a need to revise our understanding of how even the simplest electronic circuits behave at the nanoscale

In addition to the effect on the speed and efficiency of future electronic circuits, this discovery could also help to solve one of the major challenges facing future computer design. This is managing the ever-increasing amount of heat produced by integrated circuits. Well-known theorist Markus Büttiker speculates that it may be possible to harness the energy lost as heat in one wire by using other wires nearby. Moreover, Buttiker believes that these findings will have an impact on the future of both fundamental and applied research in nanoelectronics.

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The above story is reprinted from materials provided by McGill University.

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Journal Reference:

D. Laroche, G. Gervais, M. P. Lilly, J. L. Reno. Positive and negative Coulomb drag in vertically integrated one-dimensional quantum wires. Nature Nanotechnology, 2011; 6 (12): 793 DOI: 10.1038/nnano.2011.182

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Fully printed carbon nanotube transistor circuits for displays

ScienceDaily (Nov. 30, 2011) — Since the invention of liquid crystal displays in the mid-1960s, display electronics have undergone rapid transformation. Recently developed organic light-emitting diodes (OLEDs) have shown several advantages over LCDs, including their light weight, flexibility, wide viewing angles, improved brightness, high power efficiency and quick response.

OLED-based displays are now used in cell phones, digital cameras and other portable devices. But developing a lower-cost method for mass-producing such displays has been complicated by the difficulties of incorporating thin-film transistors that use amorphous silicon and polysilicon into the production process.

Now, researchers from Aneeve Nanotechnologies, a startup company at UCLA's on-campus technology incubator at the California NanoSystems Institute (CNSI), have used low-cost ink-jet printing to fabricate the first circuits composed of fully printed back-gated and top-gated carbon nanotube-based electronics for use with OLED displays. 

The startup includes collaborators from the departments of materials science and electrical engineering at the UCLA Henry Samueli School of Engineering and Applied Science and the department of electrical engineering at the University of Southern California.

In this innovative study, the team made carbon nanotube thin-film transistors with high mobility and a high on-off ratio, completely based on ink-jet printing. They demonstrated the first fully printed single-pixel OLED control circuits, and their fully printed thin-film circuits showed significant performance advantages over traditional organic-based printed electronics.

"This is the first practical demonstration of carbon nanotube-based printed circuits for display backplane applications," said Kos Galatsis, an associate adjunct professor of materials science at UCLA Engineering and a co-founder of Aneeve. "We have demonstrated carbon nanotubes' viable candidacy as a competing technology alongside amorphous silicon and metal-oxide semiconductor solution as a low-cost and scalable backplane option."

This distinct process utilizes an ink-jet printing method that eliminates the need for expensive vacuum equipment and lends itself to scalable manufacturing and roll-to-roll printing. The team solved many material integration problems, developed new cleaning processes and created new methods for negotiating nano-based ink solutions.

For active-matrix OLED applications, the printed carbon nanotube transistors will be fully integrated with OLED arrays, the researchers said. The encapsulation technology developed for OLEDs will also keep the carbon nanotube transistors well protected, as the organics in OLEDs are very sensitive to oxygen and moisture.

The technology incubator at the CNSI was established two years ago to nurture early-stage research and to help speed the commercial translation of technologies developed at UCLA. Aneeve Nanotechnologies LLC has been conducting proof-of-concept work at the tech incubator with the mission of developing superior, low-cost, high-performance electronics using nanotechnology solutions that bridge the gap between emerging and traditional platforms.

The research was published this month in the journal Nano Letters.

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The above story is reprinted from materials provided by University of California - Los Angeles.

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Journal Reference:

Pochiang Chen, Yue Fu, Radnoosh Aminirad, Chuan Wang, Jialu Zhang, Kang Wang, Kosmas Galatsis, Chongwu Zhou. Fully Printed Separated Carbon Nanotube Thin Film Transistor Circuits and Its Application in Organic Light Emitting Diode Control. Nano Letters, 2011; : 111122151948003 DOI: 10.1021/nl202765b

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