Exploring plasmonic hotspots of Au tilted nanocolumns and their application to the uracil detection by surface-enhanced Raman scattering

In this work, an investigation on plasmonic hotspots of Au tilted nanocolumns and their application to the uracil detection by surface-enhanced Raman scattering (SERS) is addressed. These Au tilted nanocolumns are fabricated by employing a low-cost and easy-to-implement fabrication technique, which is the glancing angle deposition with magnetron sputtering. Moreover, these Au nanocolumns can generate a great density of highly confined electric field zones, called hotspots, located in the nanogaps between the nearest nanocolumns. The photoemission electron microscopy is employed to obtain the statistics on the distribution of these plasmonic hotspots with a high accuracy (spatial resolution of 10–20 nm) in the spectral range from 680 nm to 1080 nm. Thus, the SERS intensity can be correlated with the density and the intensity distribution of these plasmonic hotspots. Finally, the plasmonic hotspots of the Au nanocolumns are used to assess the limit of detection (LOD) of the uracil molecule by SERS. This LOD is determined at 6 nM demonstrating the good sensitivity of our Au nanocolumns compared to the existing literature.