Lap joining of graphene flakes by current-assisted CO2 laser irradiation

A novel approach utilizing current-assisted CO2 laser irradiation was used to join two monolayer graphene flakes. Two partially overlapped graphene flakes were irradiated with a continuous wave CO2 laser, together with a current at a constant voltage of 30 V. Raman spectrometer and transmission electron microscope (TEM) analyses showed the joining signal at a laser power density of 8 W/cm2 with an irradiation time of 30 s and a current of 25 mA (30 V) for 5 min. The joining mechanism of graphene flakes was also investigated. We provide a novel route to realize large-area graphene joint for potential applications.