Stencil on graphene: a resist-free approach to multielectrode devices

Graphene gathers large interest in the scientific community due to its exotic properties. In particular, exceptionally large value of carriers mobility, and extremely high Young's modulus render graphene an outstanding candidate for future robust and high-performance electronic devices. Various lithographic approaches are nowadays used to address graphene; however, those overall modify the surface and the structure graphene, and hence its properties. Here, we present a simple single-step approach to fabricate electrodes on graphene and/or few-layers graphene by a resist-free and contamination-minimized method. Focused ion beam (FIB) patterned silicon nitride membranes are used to direct masking samples laying on a substrate; this is all carried out in ambient condition under an optical microscope. Then, metal evaporation produces electrodes for electrical testing. Further, we present our preliminary characterization of the room- and low-temperatures properties of different samples (FLG, tri- and mono-layer graphene) contacted by such technique. This method is of general use, capable of minimize contaminations and compatible with UHV technology.