Low energy ion irradiation induced SPR of Cu-Fullerene C70 nanocomposite thin films

Abstract

Metal-matrix nanocomposites have a diverse range of applications by virtue of their improved properties. However, further improvements in the characteristics of the composites can be made if we are able to tune the properties of a single constituent of the composite. In the present work, Cu-C70 thin films were grown on glass substrate with thermal co-evaporation technique. In order to induce the surface plasmon resonance (SPR) band, the nanocomposite thin films are irradiated with 120 keV N+ ion beam at the fluence ranging from 1 × 1014 to 3 × 1016 ions/cm2. The Rutherford backscattering is used to know the thickness and concentration of the components present in the nanocomposite thin film. TEM is used to show the increase in particle size of Cu nanoparticles with the increase in the irradiation fluence. The surface analysis shows a decrease in the roughness of the film upto a fluence of 3 × 1014 ions/cm2 and then the roughness increases with the increase in fluence. The UV–visible spectrum shows the formation of SPR band at ∼630 nm at the highest fluence of 3 × 1016 ions/cm2, which is ascribed to the increase in the size of the Cu nanoparticles. The FTIR spectrum shows various bonds of copper - fullerene nanocomposite in pristine film. Raman spectroscopic investigations show the transformation of fullerene C70 matrix of Cu-C70 thin film into amorphous carbon matrix at higher fluences. XPS is also performed to show the elemental state of composite material.