Synthesis of graphene nanosheets from indium-catlyzed graphite using electron beam irradiation

The graphene nanosheets have the high surface volume ratio due to its sharp edges and open structures, and it can be advantage for electrical applications such as gas detection, gas storage and batteries that are required high electrical mobilities. The conventional methods to synthesize graphene nanosheets are chemical vapor deposition (CVD), electrophoretic deposition, salt-tmeplating methods. However, these methods have still limitation because of difficulties in the preparation of large scale, dense graphene nanosheets. Here, we present a simple and convenient route to synthesize the graphene nanosheets by electron beam irradiation to indium (In) and graphite mixture. In vacuum furnace, graphite was degraded by the indium catalyst at high temperature. Furthermore, carbon atoms from degraded graphite are rearranged to graphene nanosheets by indium catalyst. In spired by these, we tried to fabricate graphene nanosheets from indium-catalyzed graphite using electron beam irradiation. When an electron beam is irradiated, the electron beam gives heat and a large amount of energy to mixed graphite and indium, thus indium is easily activated to degrade the graphite and combine the carbon atoms into graphene. This process doesn't need high pressure gas and temperature, so it is more safety than other synthesis methods. In this study, 2 types of indium, sputtered In and In particles, was used to fabricate the graphene nanosheets to determine the appropriate In catalyst type. The 50keV electron beam device manufactured by our laboratory is used and the morphology of graphene nanosheets are confirmed through the scanning electron microscopy (SEM).