Tunable surface plasmon resonances in sputtered titanium nitride thin films

Thin films of titanium nitride were deposited on alpha-brass and gold electroplated brass (GCB) substrates by DC reactive magnetron sputtering at different N2 partial pressures (10%, 50% and 100 %). The measured specular reflectance spectra of the films indicate the existence of surface plasmon resonance peaks whose positions are dependent on the substrate and nitrogen pressure during deposition. In the case of films on brass, the SPR (surface plasmon resonance) is centered around 600, 550 and 510 nm at 10,50 and 100% Nitrogen. In contrast, the SPR occurs at 510 nm for the films deposited at 10% and 50% nitrogen which red shifts to 570 nm for the film deposited in 100% nitrogen. The observed behavior is correlated with morphology, microstructure and structure of the films.