Study on Cu-fullerene C70 nanocomposite thin films under electronic excitations

Abstract

Modifications and tailoring the properties of the fullerene based nanocomposites have always been the field of interest due to its wide range of applications in optoelectronic devices and sensors. Cu-C70 nanocomposite thin films were synthesized and investigated under electronic excitations. Cu-C70 thin films are irradiated with 120 MeV Ag ions at a fluence ranging from 1 × 1012 ions/cm2 to 3 × 1013 ions/cm2. The energetic ion impacts lead to the surface modifications which are investigated by scanning electron microscopy and atomic force microscopy. The roughness of the nanocomposite film first increases drastically and then a decrease is observed. Transmission electron microscopy shows well-shaped Cu nanoparticles in pristine films and the increase in the crystallinity is observed with increasing fluence of 120 MeV Ag ion beam. The ion irradiation results in destruction of C70 fullerene with increasing fluence as confirmed by Raman spectroscopy. The elemental state of all the elements in the sample is verified by x-ray photoelectron spectroscopy. Finally, the decrease in resistance with increasing fluence is observed by two probe I-V measurements. Conductivity measurement together with Raman and optical absorption study reveal the amorphization of C70 fullerene at highest fluence of 3 × 1013ions cm-2.