Ion irradiation studies of silver/amorphous carbon nanocomposite thin film

We study the optical and microstructural properties of silver/amorphous carbon (Ag/a-C) nanocomposite thin film and its modification induced by swift heavy ion irradiation. Ag nanoparticles (NPs) embedded in a-C matrix were synthesized by co-sputtering of Ag and graphite by 1.5 keV neutral Ar atom beam. These Ag NPs were irradiated by 120 MeV Ag ions at different fluences ranging from 1 x 10(12) to 3 x 10(13) ions/cm(2). Optical absorption studies revealed that surface plasmon resonance of Ag NPs in pristine film occurs at a wavelength of similar to 430 nm and it shows a blue shift (similar to 26 nm) with increasing ion fluence up to 3 x 10(13) ions/cm(2). Transmission electron microscopy and Rutherford backscattering spectroscopy were used to quantify particle size and metal atomic fraction, respectively, in the nanocomposite films. The growth of Ag NPs with hi-model distribution at a fluence of 3 x 10(13) ions/cm(2) was observed with ion irradiation. Raman spectroscopy was used to investigate the effect of heavy ion irradiation on carbon matrix. The blue shift in plasmonic wavelength is explained in terms of increase in sp(2) content in carbon matrix by heavy ion irradiation due to thermal energy deposition which leads to a decrease in dielectric properties of the matrix