Electronic excitation induced modifications of structural, electrical and optical properties of Cu-C-60 nanocomposite thin films

Abstract

High energy ion irradiation significantly affects the size and shape of nanoparticles in composites. Low concentration metal fraction embedded in fullerene matrix in form of nanocomposites was synthesized by thermal co-evaporation method. Swift heavy ion irradiation was performed with 120 MeV Au ion beam on Cu-C-60 nanocomposites at different fluences 1 x 10(12), 3 x 10(12), 6 x 10(12), 1 x 10(13) and 3 x 10(13) ions/cm(2). Absorption spectra demonstrated that absorption intensity of nanocomposite thin film was increased whereas absorption modes of fullerene C-60 were diminished with fluence. Rutherford bacicscattering spectroscopy was also performed to estimate the thickness of the film and atomic metal fraction in matrix and found to be 45 nm and 3%, respectively. Transmission electron microscopy was performed for structural and particle size evaluation of Cu nanoparticles (NPs) in fullerene C-60 matrix. A growth of Cu nanoparticles is observed at a fluence of 3 x 10(13) ions/cm(2) with a bi-modal distribution in fullerene C-60. Structural evolution of fullerene C-60 matrix with increasing fluence of 120 MeV Au ion beam is studied by Raman spectroscopy which shows the amorphization of matrix (fullerene C-60) at lower fluence. The growth of Cu nanoparticles is explained using the phenomena of Ostwald ripening