Effect of Ag Ion Implantation on SPR of Cu-C60 Nanocomposite Thin Film

Abstract

Cu-C60 nanocomposite thin films are synthesized by co-deposition restive heating method on glass, silicon, and TEM grid substrates. Rutherford backscattering spectroscopy (RBS) analysis is used for determining the composition of Cu and thickness of thin film which one found to be ∼13 at% and ∼28 nm, respectively. The deposited thin films are irradiated with 100 keV Ag ion at different fluences ranging from 1 × 1014 to 3 × 1016 ions/cm2. Being of low energy, Ag ions got implanted in SiO2 substrate up to a depth of 30–40 nm that results in wide surface plasmon resonance (SPR) band in combination with SPR of Cu nanoparticles. UV-visible absorption spectroscopy demonstrates the SPR peak arises due to copper nanoparticles embedded in fullerene C60 matrix on irradiation of nanocomposite thin film and its variation under implantation of Ag nanoparticles in SiO2 substrate. Structural modifications due to ion irradiation are analyzed by Raman and transmission electron microscopy (TEM). Raman spectroscopy study reveals the transformation of fullerene C60 into amorphous carbon (a-C) with increasing fluence. Variation in particle distribution is observed under TEM. The average particle sizes are found to be ∼4 ± 0.7 and ∼6 ± 0.4 nm for pristine and 100 keV Ag ion-irradiated thin films, respectively. Atomic force microscopy (AFM) confirms the increase in grain size with increase in roughness of nanocomposite thin films under the effect of implantation. X-ray photoelectron spectroscopy (XPS) confirms the presence of Cu and C from their chemical bonding in Cu-C60 nanocomposite thin films.