Enhanced morphological stability of silver nanoparticles supported on rough substrates at high temperatures

Noble metal nanostructures serve as excellent substrates for the detection of trace amounts of substances in surface enhanced Raman spectroscopy, but they have not found widespread commercial use due to their instability and short shelf lives. This work demonstrates that silver nanoparticles grown onto substrates with nanoscale roughness, using glancing angle physical vapour deposition and subsequently thermally annealed at 500°C to generate a stable lower energy configuration, exhibit Raman enhancements that are strong and remain stable with no drop over 30 days. These nanoparticle arrays may serve as time stable substrates for commercial scale Raman spectroscopy or may be employed in harsh environments.