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

摘要

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 1012, 3 x 1012, 6 x 1012, 1 x 1013 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 backscattering 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 1013 ions/cm2 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.