C. Process Summary
Schematic of graphene electrical probing and sensor fabrication is described here. First the graphene layer is prepared on top of the transparent Pyrex glass surface and imaged using the inverted microscope (Fig. 3a). This setup has proved to be useful for manipulation mainly because of transparent optical characteristics of graphene layer and enough space to install manipulators on top of the microscope sample stage. Then 2 picoprobes mounted to the Kleindiek manipulators are used to characterize electrical transport properties of the graphene sample (Fig. 3b). A metal probe (Picoprobe, T-4-10-1 mm, tip radius: ~100nm) mounted on the nanomanipulator was used. Thirdly the gold electrode is
created by fountain-pen based gold nanoink deposition. Once
the graphene layer is electrically characterized, the fountainpen
method was used to pattern the electrodes [14] (Fig. 3c).