Next generation SERS- atomic scale platform for molecular level detection

Abstract The research with ultra-sensitive detection by Raman enhancement has traditionally focused on Surface Enhanced Raman Scattering (SERS) or Tip Enhanced Raman Scattering (TERS) from predominantly Raman active materials (monolayers of metallic nanoparticles of gold and silver). However, these traditional SERS & TERS methods have demonstrated limited applicability due to many inherent disadvantages. In this study, we have demonstrated the next generation of Enhanced Raman Sensing by adding a third dimension, by introducing a concept of employing atomic scale features (voids in nanostructures) for molecular level detection. Unlike traditional SERS/TERS, the atomic scale platform also exhibited immunity to the excitation wavelength showing potential for universal sensor. Additionally, this portable platform demonstrated a wide spectrum of applications from trace level detection of environmental pollutants, Raman reporter molecule sensing, detection of biomarkers associated with cancer and detection of cancer from the DNA, opening new doors for many non-invasive, ultrasensitive and remote sensing applications. The atomic scale platform was synthesized with two features- multi-tip probes encapsulated with multiple layers of atomic scale voids. Multi-photon ionization mechanism was used for the synthesis. We have witnessed exponentially increased and highly reproducible Raman enhancement from a traditionally Raman inactive material (semiconductor based ZnO) demonstrating molecular level detection. Utilization of atomic-scale features (voids in nanostructures) for activation of a typically Raman inactive material for molecular level detection will create a paradigm for future studies in the field of Raman enhancement for Raman active as well as Raman inactive materials. This mechanism will initiate avenues for many new materials to be candidates for Raman sensing.