Linear arrays of nanotubes offer path to high-performance electronics

March 25, 2007

Despite the attractive electrical properties and physical features of single-walled carbon nanotubes, incorporating them into scalable integrated circuits has proven to be a challenge because of difficulties in manipulating and positioning these molecular scale objects and in achieving sufficient current outputs.

Now, researchers at the University of Illinois, Lehigh University and Purdue University have developed an approach that uses dense arrays of aligned and linear nanotubes as a thin-film semiconductor material suitable for integration into electronic devices.

The nanotube arrays can be transferred to plastic and other unusual substrates for applications such as flexible displays, structural health monitors and heads-up displays. The arrays also can be used to enhance the performance of devices built with conventional silicon-based chip technology.

"The aligned arrays represent an important step toward large-scale integrated nanotube electronics," said John A. Rogers, a Founder Professor of Materials Science and Engineering at Illinois, and corresponding author of a paper accepted for publication in the journal Nature Nanotechnology, and posted on its Web site.

To create nanotube arrays, the researchers begin with a wafer of single-crystal quartz, on which they deposit thin strips of iron nanoparticles. The iron acts as a catalyst for the growth of carbon nanotubes by chemical vapor deposition. As the nanotubes grow past the iron strips, they lock onto the quartz crystal, which then aligns their growth.

The resulting linear arrays consist of hundreds of thousands of nanotubes, each approximately 1 nanometer in diameter, and up to 300 microns in length. The nanotubes are spaced approximately 100 nanometers apart.

The arrays function as an effective thin-film semiconductor material in which charge moves independently through each of the nanotubes. In this configuration, the nanotubes can be integrated into electronic devices in a straightforward fashion by conventional chip-processing techniques.

A typical device incorporates approximately 1,000 nanotubes, and can produce current outputs 1,000 times higher than those of previously reported devices that incorporate just a single nanotube. Many devices can be built from each array, with good device-to-device uniformity. Detailed theoretical analysis of these unusual devices reveals many aspects of their operation.

Using the arrays, the researchers built and tested a number of transistors and logic gates, and compared the properties of nanotube arrays with those of individual nanotubes.

"This is the first study that shows properties in scalable device configurations that approach the intrinsic properties of the tubes themselves, as inferred from single-tube studies," said Rogers, who also is a researcher at the university's Beckman Institute.

Nanotube arrays aren't likely to replace silicon, Rogers said, but could be added to a silicon chip and exploited for particular purposes, such as higher speed operation, higher power capacity and linear behavior for enhanced functionality. They can also be used in applications such as flexible devices, for which silicon is not well suited.

"Nanotubes have shown potential in the past, but there hasn't been a clear path from science to technology," said Moonsub Shim, a professor of materials science and engineering at Illinois, and a co-author of the paper. "Our work seeks to bridge this gap."

Source: University of Illinois at Urbana-Champaign

Explore further: Programmable disorder: Random algorithms at the molecular scale

Related Stories

For first time, carbon nanotube transistors outperform silicon

September 2, 2016

For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power—resulting in longer battery life, faster wireless communication ...

Apple patent reveals idea for fingerprint technology

October 6, 2016

(Tech Xplore)—"Capacitive fingerprint sensor including an electrostatic lens" is the title of the patent filed in September 2014.The inventor listed is Jean-Marie Bussat. This is being talked about in this week's tech press ...

New applications for ultracapacitors

September 8, 2016

Devices called ultracapacitors have recently become attractive forms of energy storage: They recharge in seconds, have very long lifespans, work with close to 100 percent efficiency, and are much lighter and less volatile ...

Recommended for you

New aspect of atom mimicry for nanotechnology applications

December 2, 2016

In nanotechnology control is key. Control over the arrangements and distances between nanoparticles can allow tailored interaction strengths so that properties can be harnessed in devices such as plasmonic sensors. Now researchers ...

Engineers create prototype chip just three atoms thick

November 29, 2016

For more than 50 years, silicon chipmakers have devised inventive ways to switch electricity on and off, generating the digital ones and zeroes that encode words, pictures, movies and other forms of data.

Nanotechnology a 'green' approach to treating liver cancer

November 29, 2016

According to the American Cancer Society, more than 700,000 new cases of liver cancer are diagnosed worldwide each year. Currently, the only cure for the disease is to surgically remove the cancerous part of the liver or ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.