Surface plasmon effect in nanocrystalline copper/DLC composite films by an electrodeposition technique

Composite films of nanocrystalline copper embedded in diamond-like carbon (DLC) matrix were deposited on SnO2-coated glass substrates by using an electrochemical technique. Particle size and metal volume fraction were tailored by varying the amount of copper containing salt (copper acetate) in the electrolyte. Red-shift of the surface plasmon resonance peak in the optical absorbance spectra of the films was observed with the reduction in size and increase in volume fraction of metal particles. Surface plasmon peak was not observed in the absorption spectra below a critical particle size and metal concentration of the nanoncomposite films. Mie scattering theory was found to describe the experimental spectra better than the Maxwell-Garnett (M-G) effective medium theory.