Variability of graphene devices fabricated using graphene inks: Atomic force microscope tips

During the last decade, an uncountable amount of graphene prototype devices have been reported, but unfortunately none of them has faced mass production and commercialization. One of the main reasons is that graphene technologies are highly affected by variability problems. Although graphene presents almost unbeatable chemical and physical properties, the development of graphene devices has been heavily hindered by the difficulty of fabricating homogeneous and identical devices, due to the presence of uncontrollable amounts of defects. One of the most preoccupying aspects in the development of graphene technology is the lack of reported variability studies. Here we present the first thorough variability analysis for a graphene device, namely graphene-coated nanoprobes for atomic force microscopes. The relevancy of this work is increased by the use of a fabrication method capable of large scalability: liquid-phase exfoliated graphene inks. Our results indicate that, for this device, the presence of graphene does not introduce any performance deviation indicating that, from the variability point of view, this device is ready for mass production. Similar variability analyses should be applied to other devices in order to detect which graphene technologies are not affected by variability problems, facilitating them the introduction of graphene prototypes in the market.