Graphene formation at 150 degrees C using indium as catalyst

Graphene is generally synthesized at high temperatures. Here we demonstrate a simple method to synthesize graphene at 150 degrees C. Carbon foils were irradiated with Ar+ ions at 1 keV with a simultaneous supply of catalyst metal without any intentional heating to survey the novel catalyst for graphene growth at low temperature. The ion irradiated surfaces were covered with densely distributed conical structures sometimes with a nanofiber on their respective tips. As revealed by high resolution (HR) transmission electron microscopy (TEM), the conical tips featured few layer graphene only for the newly selected catalyst metal, In, which is rarely used for the chemical vapor deposition (CVD) synthesis of graphene. This observation gives a new insight into the catalytic activity during graphene synthesis. Encouraged by this ion-induced graphene formation, samples of a thin, amorphous carbon film on SiO2 substrates overlaid with this novel catalyst film were prepared, and finally, graphene growth was achieved by simple vacuum heating at 150 degrees C.