Optimizations of Sealing Conditions for Blank Silver Nanorod Used as SERS Substrates

Silver nanorods, prepared on Si substrates by sputtering deposition with the technique glancing-angle deposition (GLAD), were used as surface-enhanced Raman scattering (SERS) substrates. The prepared samples were categorized into two groups based on sealing conditions after the nanorod fabrications. The non-sealed SERS substrates were prepared by purging in the vacuum chamber with argon, oxygen, and ambient air. The sealed SERS substrates were enveloped with several types of packages, i.e., petri dishes, plastic bags, and foils, where they were all handled in a controlled glove box. The samples were characterized by field-emission scanning electron microscopy (FESEM) for the physical morphologies. The samples were further investigated by Raman spectroscopy for Raman spectra of blank substrates of each condition. The results showed that, in case of the non-sealed category, the SERS substrates purged under the argon gas was best optimized to prevent ambient contamination during prolonged period of time. In the case of the sealed category by different packages, the SERS substrates demonstrated the enhancement of the Raman-shift spectra with very small unwanted peaks, and in addition the extended lifetime.