Graphene‐Coated Atomic Force Microscope Tips for Reliable Nanoscale Electrical Characterization

Abstract

Graphene single-layer films are grown by chemical vapor deposition and transferred onto commercially available conductive tips for atomic force microscopy. Graphene-coated tips are much more resistant to both high currents and frictions than commercially available, metal-varnished, conductive atomic force microscopy tips, leading to much larger lifetimes and more reliable imaging due to a lower tip-sample interaction.

Graphene Coated Nanoprobes: A Review

“…Finally, all the PMMA was removed via acetone vapor. This is the most critical step of this technique, as highlighted by the authors [24]. Basically, a very ingenious method was proposed to remove the PMMA in this work, that is, instead of liquid acetone, a large amount of PMMA was sufficiently removed by boiling acetone vapor (~68 • C) for 30 min.…”

“…One of the main advantages of CVD-grown 2D materials is that they can be prepared on a substrate that ensures very high quality (e.g., Cu foils) and is then transferred onto the target device. Lanza et al [24] coated commercially available AFM probes with a sheet of graphene previously grown on a Cu foil. During the fabrication process two samples were prepared independently and merged (see Figure 2a).…”

“…Step-by-step schematic of the process followed to transfer graphene (grown on Cu foils) onto AFM tips. Reproduced with permission from [24], copyright Wiley-VCH (2013): (b) Experimental protocol used to fabricate graphene coated tip arrays. Reproduced with permission from [25], copyright AAAS.…”

“…The emergence of two dimensional (2D) materials with superior properties (mechanical strength, flexibility, transparency, thermal conductivity, chemical stability, among others) [19][20][21][22], has also been attractive in the field of conductive nanoprobes engineering. Several works [23][24][25][26][27][28][29] have demonstrated that graphene would be an ideal coating material to enhance the lifetime of a conductive nanoprobe, as it can provide high conductivity and mechanical robustness without increasing the tip radius (it is just one atom thick) and/or modifying the spring constant of the cantilever (its mass is negligible, while hard coatings like diamond have a considerable mass that bend the cantilevers and alter their mechanical and dynamic properties). Furthermore, graphene could be used to functionalize the surface of the probes, providing additional properties like hydrophobicity and piezoelectricity.…”

Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

“…However, tips modified with gold nanoparticles have also shown good resolution and sensitivity for graphene imaging [71]. Conductive tips fabricated by coating commercially available metal-varnished tips with graphene showed very high resistance to both high currents and frictions, leading to much longer lifetimes and preventing false imaging due to tip-sample interaction [72,73].…”