Nanostructures build next-gen lab equipment
new building block for creating laboratory equipment that rely on
electromechanical coupling. The material's cost and flexibility
makes it suitable for biomedical applications, which use silicon
technology.
The structure, resembling the helical configuration of DNA, could provide engineers with a new building block for creating nanometer-scale sensors, transducers, resonators and other devices that rely on electromechanical coupling.
Scientists from the Georgia Institute of Technology are confident that this unique material could become the new material for nanotechnology following carbon nanotubes.
The nanohelices reach lengths of up to 100 microns, with diameters from 300 to 700 nanometers and widths from 100 to 500 nanometers.
Based on a superlattice composed of alternating single-crystal "stripes," the "nanohelix" structure is part of a family of nanobelts - tiny ribbon-like structures with semiconducting and piezoelectric properties.
"This structure provides a new building block for nanodevices," said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology.
"From them we can make resonators, place molecules on their surfaces to create frequency shifts - and because they are piezoelectric, make electromechanical couplings. This adds a new structure to the toolbox of nanomaterials," he added.
This structure illustrates a new growth model for nanomaterials having semiconducting and piezoelectric properties that makes them good for electromechanical coupling.
A wideband semiconductor, zinc oxide has interesting piezoelectric and optical properties producing ultraviolet laser emissions and electroluminescence at room temperature. Those properties make it potentially useful in many applications.
The first dozen batches of nanohelices produced a yield of only about 10 per cent, but Wang believes that can be improved over time.
Thus far, Wang's research team has produced nearly 20 different zinc oxide nanostructures, including nanobelts, aligned nanowires, nanotubes, nanopropellor arrays, nanobows, nanosprings, nanorings, nanobowls and others. And there may yet be other structures discovered.
"You never know what other structures might be out there that could be added to this toolbox," he said. "From the richness of this configuration and the complete properties, this is a unique material that could become the new material for nanotechnology following carbon nanotubes."
Information about the growth and analysis of the new structures is reported in the September 9 issue of the journal Science.
