Highly pure nanotubes needed for next generation electronic devices

A University of Arkansas at Little Rock chemistry professor, his post-doctoral student, and colleagues at Stanford University, have developed a technique that could break through bottleneck that so far has stymied the scientific quest to create a new generation of electronic systems on the nano-scale.

Dr Wei Zhao, professor in UALR's Department of Chemistry in the College of Science and Math, and his graduate student Xiaomin Tu, now a postdoctoral fellow at DuPont Central Research and Development, Wilmington, Del., are co-authors of an article in the latest edition of the Journal of the American Chemistry Society on the ability to achieve near single type purity nanotube production.

The UALR professor said semi-conducting single-walled carbon nanotubes (SWNTs) with diameter of about one nanometre have attracted the most attention as a new generation material, a possible replacement for silicon for nanoelectronics. Scientists have been unable produce the kind of uniform type of nanotubes the electronic systems would need. The UALR team found a way.

'Our current work combines selective growth of a few nanotubes with chromatographic separation to achieve near single type purity nanotube production - a big step toward the SWNT applications,' Zhao said.

'The semiconductor industry has been improving the performance of electronic systems for more than four decades by making ever-smaller devices down to nanometre scale. However, this approach will soon encounter both scientific and technical limits.'

Semiconducting single-walled carbon nanotubes have attracted the most attention as a new generation material, a possible replacement for silicon for nanoelectronics. However, the structural heterogeneity with various types of nanotubes of different diameters and chiralities is the bottleneck for SWNT electronic, photonic, and optoelectronic applications where single type nanotube purity is required, Zhou said. His work combines selective growth of few nanotubes with chromatographic separation to achieve near single type purity nanotube production, a big step toward the SWNT applications.

Dr Michael Gealt, dean of the College of Science and Mathematics at UALR, said the availability of pure single-wall nanotubes will greatly enhance the creation of new products useful for the consumer.

'Dr Zhao's technique promises to provide industry with a critical starting material for development of manufactured goods with greater electrical efficiency, thereby helping to conserve electricity while making products that work better,' Gealt said.

The UALR-Stanford discovery has generated major buzz in chemical and nanotechnology circles.

'The day of being able to pick and choose single-walled nanotubes with defined electrical properties may soon be upon us,' said science writer Jon Evans, reviewing the discovery in the Ion Chromatography, an online science magazine.