Surface enhanced Raman scattering on ion-beam-deposited TiN_x/Si substrates

Titanium nitride (TiN_x) thin films were fabricated on silicon substrates by ion beam deposition. The surface enhanced Raman scattering (SERS) effect of the TiN_x/Si substrates was studied with Rhodamine 6G as probe molecule. The results show that TiN_x thin films can enhance the Raman signal, and the film with suitable thickness can significantly improve the SERS performance. For the 30 nm thick TiN_x thin films the enhancement factor is up to 6.6×10⁴. The enhancement factor can be further improved several times by assisting ions. The main role of the assisting ions is to enhance the intensity and density of hot spots through the modification of surface morphology and plasmons. The study implies that high carrier concentration, and suitable size and high density of the grains and gaps are important for improving SERS performance. This work indicates the promising future of TiN_x and assisting ions in the development of SERS active templates.