Polarization-based surface enhanced Raman scattering from single colloidal DNA decorated with 3 nm silicon nanoparticles

Kevin Mantey, Lucia Quagliano, Ayman Rezk, Simonetta Palleschi, Laila Abuhassan, Ammar Nayfeh, Ersin Bahceci, Munir H. Nayfeh

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Surface enhanced Raman scattering (SERS), in which sample molecules are placed in the proximity of conducting nanostructures, subjects the molecules to intense electron oscillation (plasmon) field. The intense field, however, may cause heavy distortion and thermal damage to the molecule as well as non-separable and heavy convolution with the metal electronic structure. We utilized 3-nm red luminescent Si nanoparticles decorating the DNA molecules (drawn electrostatically) to enhance Raman scattering in solution at 532 nm. We demonstrated that the nanoparticles enhance the spectral resolution and intensity of vibrations of DNA by two orders of magnitude and reveal vibrations that are otherwise weak or forbidden. Theoretically, we conducted calculations of Mie scattering and three-dimensional finite-difference time-domain scattering and obtained the wavelength dependence of the near-field distribution from single or dimer Si particles. The simulations show moderate intensity enhancement (25-40-fold) and exciton resonances. Moreover, it shows that the near field is highly confined, extending only to 3-5 Å from the Si particle (atomic scale) compared to several nanometers for metal nanoparticles. The observed SERS-type characteristics are understood in terms of polarization-based light scattering, which is possible by the use of Si of highly reduced size for which the polarizability and exciton processes are strong. However, multilayers contribute to metal SERS, and monolayers/single molecules dominate the Si case. Weaker but highly confined, ultra-short range polarization-based scattering provides an alternative to plasmon and Mie scattering, while providing practical, straightforward interpretation of vibration printing of bio-medical species without compromising the molecular structure.

Original languageBritish English
Article number105206
JournalAIP Advances
Issue number10
StatePublished - 1 Oct 2021


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