Raman spectroscopy, a method that uses scattered laser light to identify molecules, has become increasingly critical to identify and characterize specimens on the molecular-scale. However, the technique has a limited ability to identify molecules in diluted specimens due to low signal yield.

To address this issue, a team of scientists from the University of Hyderabad in India has enhanced the molecular detection of Raman spectroscopy at low concentrations by organizing silver nanoparticles on nanowires in specific arrangements. The development, outlined in a new study published by the Journal of Applied Physics, is a big step forward for surface-enhanced Raman spectroscopy (SERS), which uses electromagnetic fields to boost Raman scattering and responsiveness in conventional dyes by greater than one billion times.

In the new study, the team appointed vertically-arranged silicon nanowires with various densities of silver nanoparticles, making use of and enhancing the structure’s form. By doing this, the team was able to strengthen the Raman signals for cytosine protein and ammonium perchlorate by 100,000 times.

“The beauty is that we can improve the density of these nanowires using simple chemistry,” study author Soma Venugopal Rao, a professor at Hyderabad, said in a news release. “If you have a large density of nanowires, you can put more silver nanoparticles into the substrate and can increase the sensitivity of the substrate.”

Past efforts have applied nanostructures to SERS devices with limited success. Three dimensional structures made with silicon nanowires has gotten attention for their exceptional performance, but silicon nanowires are costly to create.

Image Credit:  Schlyx/shutterstock

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