Swift Heavy Ion Induced Optical and Electronic Modifications of Graphene-TiO2 Nanocomposites

The effect of swift heavy ions irradiation on optical and electronic properties of chemically synthesized graphene-TiO2 nanocomposites is presented. Modification of surface properties of these nanocomposites by irradiation with three different ions and with varying fluence was analyzed by Raman spectroscopy, transmission electron microscopy, and scanning Kelvin probe microscopy techniques. Raman spectra of irradiated samples exhibit systematic changes in the characteristic peaks of both graphene and TiO2. The nanocrystallite dimension calculated from Raman peak intensity decreases with fluence, indicating the occurrence of peripheral fragmentation. Furthermore, measurement of the surface contact potential difference using scanning Kelvin probe reveals that the work function of graphene-titanium dioxide nanocomposites can be effectively increased by more than 1 eV.