Electronic excitation induced modifications of Au-Carbon nanocomposite

Abstract

Annealing of Au-C (Au and amorphous carbon) nanocomposite thin samples prepared by sputtering is performed at a temperature of 500 °C in order to get uniformity of Au nanoparticles. Size modifications of Au NPs (nanoparticles) and tuning of SPR(Surface Plasmon Resonance) wavelength of annealed nanocomposite thin samples of Au-C are investigated under electronic excitation. For annealed Au-C thin samples, irradiation is done by a beam of 120 MeV Ag ions at a fluence ranging from 1e12 ions cm−2 to 3e13 ions cm−2. The variation of energy loss in annealed and Ag ions irradiated Au-C nanocomposite thin films shows the dominance of electronic energy loss (Se) over nuclear energy loss (Sn). A blue shift of about ∼16 nm for irradiation at the fluence from 1e12 ions cm−2 to 1e13 ions cm−2 is obtained as confirmed by UV-visible absorption spectroscopy and ∼28 nm red shift for irradiation at a fluence of 3e13 ions cm−2 is achieved. Size of the Au NPs is increased by ∼10.8 nm due to annealing at 500 °C temperature and further enhancement in the size of Au NPs up to ∼17.2 nm is recorded due to irradiation at a fluence of 3e13 ions cm−2 which is verified by Transmission Electron Microscopy (TEM). The nature of amorphous carbon matrix is confirmed by the presence of D and G band in Raman spectroscopy in the nanocomposite thin film.