'Nanowire Monolayers' Offer Nanotechnology Applications

By Roland Piquepaille

"The most important thing right now is that this technique allows us to do large-scale assembly of wires," said UC Berkeley chemistry professor Peidong Yang, who is also a chemist at the Lawrence Berkeley National Laboratory.

Yang's technique, known as Langmuir-Blodgett Assembly, allows creation of monolayers of nanowires up to three square inches in area.

"We call this a Self-Assembled Monolayer, or SAM," said Andrea Tao, a graduate student in Yang's lab. "By developing this new technique, we have been able to mass produce these monolayers so that they become more practical for scientific use."

Here is a spectacular photograph of these monolayers of nanowires (Credit: Bhuvan Jain).

What will we do with these nanowires?

The monolayers can be placed onto surfaces such as plastics, polymers, glass, silicon and even soft, flexible surfaces.

With so many possibilities, the nanowires can be used as active components in solar cells, light-emitting diodes and other optics to enhance electromagnetic signals.

The researchers also are targeting surface-enhanced Raman spectroscopy.

In surface-enhanced Raman spectroscopy, the nanowire monolayers can aid in better vibrational spectrum signals than a flat surface can. This allows for better detection of more and smaller chemicals.

With improved Raman spectroscopy, chemical and biological species can be detected with much more accuracy. This can be important in national and global security as explosives always give off tell-tale chemical vapors.

Source: Kevin Wu, The Daily Californian, October 8, 2003