Light-Trapped Nanocavities For Ultraviolet Surface-Enhanced Raman Scattering

The fabrication of surface-enhanced Raman scattering (SERS) substrates with large areas, high activities, desirable uniformities, and aggregated hot spots evenly distributed in the UV (ultraviolet) region has been regarded as a formidable task. In the present work, by means of elaborate structure designs and material selections, we have fabricated periodic light-trapped nanocavities that have overcome the abovementioned difficulties. Specifically, a great amount of electromagnetic energy has been localized in nanocavities due to repeated reflections of the trapped incident light, thus re-amplifying abundant hot spots of the aluminum film. At an excitation wavelength of 325 nm, the acquisition of ultrahigh SERS enhancement factors (greater than or similar to 10(6)) has been successfully achieved, and signal intensities are uniformly distributed after repeated measurements. In the originally weak UV region, our nanostructure design and its associated mechanism may provide a guide for future SERS-related research.