Silver-decorated aligned CNT arrays as SERS substrates by high temperature annealing

A feasible way to synthesize a surface-enhanced Raman scattering (SERS) substrate has been developed, where Ag nanoparticles (AgNPs) of different size and morphology are assembled on the surface and sidewalls of the aligned carbon nanotube (CNT) arrays via magnetron sputtering and high-temperature annealing. Our results show that the optimized substrate is performed by annealing temperature at 450 °C for 30 min. The state of the obtained AgNPs makes a significant contribution to the high sensitivity of SERS to R6G molecules, and the substrate has an enhancement factor (EF) on the order of ~10¹⁰. Meanwhile, the Ag/CNT arrays keep a good reproducibility with the average RSD values being less than 0.01 for all major Raman peaks. The temporal stability of our substrates has been also appeared, which indicates that the Ag/CNT arrays can be used as stable substrates for the production of enhanced SERS signals for up to three months under ambient conditions.