---

New kid on the plasmonic block

With its promise of superfast computers and ultrapowerful optical microscopes among the many possibilities, plasmonics has become one of the hottest fields in high-technology. However, to date plasmonic properties have been limited to nanostructures that feature interfaces between noble metals and dielectrics. Now, researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory have shown that plasmonic properties can also be achieved in the semiconductor nanocrystals known as quantum dots. This discovery should make the field of plasmonics even hotter.

“We have demonstrated well-defined localized surface plasmon resonances arising from p-type carriers in vacancy-doped semiconductor quantum dots that should allow for plasmonic sensing and manipulation of solid-state processes in single nanocrystals,” says Berkeley Lab director Paul Alivisatos, a nanochemistry authority who led this research. “Our doped semiconductor quantum dots also open up the possibility of strongly coupling photonic and electronic properties, with implications for light harvesting, nonlinear optics, and quantum information processing.”

Alivisatos is the corresponding author of a paper in the journal Nature Materials titled “Localized surface plasmon resonances arising from free carriers in doped quantum dots.” Co-authoring the paper were Joseph Luther and Prashant Jain, along with Trevor Ewers.

The term “plasmonics” describes a phenomenon in which the confinement of light in dimensions smaller than the wavelength of photons in free space make it possible to match the different length-scales associated with photonics and electronics in a single nanoscale device. Scientists believe that through plasmonics it should be possible to design computer chip interconnects that are able to move much larger amounts of data much faster than today’s chips. It should also be possible to create microscope lenses that can resolve nanoscale objects with visible light, a new generation of highly efficient light-emitting diodes, and supersensitive chemical and biological detectors. There is even evidence that plasmonic materials can be used to bend light around an object, thereby rendering that object invisible.