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

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. (paper)