• [2013-03-21]

  Huiling Duan’s research group fabricates a graphene-prototype for reliable nanoscale electrical characterization

Researchers at Professor Huiling Duan’s group recently developed a new graphene based device for reliable nanoscale electrical characterization. The invention, which has been patented and has attracted the interest of the industry, has been published recently in the prestigious magazine Advanced Materials under the title "Graphene-Coated Atomic Force Microscope Tips for Reliable Nanoscale Electrical Characterization" (Adv. Mater. 2013, 25, 1440–1444).

Since its first synthesis in 2004, graphene has attracted the attention of many researchers and scientists. Many works have been devoted to analyze the intrinsic properties of the material itself, and exciting findings have been made. In this field, Professor Duan’s group reported a couple of months ago an interesting dependence between Graphene morphology and substrate roughness (Journal of Applied Physics 113, 104301, 2013). But to date, not many graphene-based devices with a realistic use in the industry have been reported.

The prototype developed by Dr. Lanza in Duan’s team and co-workers consists of coating a commercially available CAFM tip with a monolayer sheet of Graphene, taking advantage of its genuine properties, such as high conductivity and mechanical resistance. To do so, due to the complex shape of CAFM tips, they had to modify the standard transfer process to avoid tip lateral and vertical shifts. Using Scanning Electron Microscope and Energy-dispersive X-ray Spectroscopy the authors empirically prove the preservation of the tips shape and the presence of graphene on the tips. Graphene-coated tips have been used to analyze the properties of some nanostructured materials at the nanoscale using spectroscopic current-voltage curves and, for the first time, current maps. The results reveal that, after the graphene coating, the tips acquired an unusual high resistance to high currents and mechanical frictions, as well as avoid tip sample interactions that could produce false data, leading to the most reliable CAFM tips fabricated to date. Leading companies in the field of nanotechnology devices already showed their interest on this invention.

Paper link: http://onlinelibrary.wiley.com/doi/10.1002/adma.201204380/full

Figure 1: Schematic of an (a) as-received and (b) graphene-coated commercial available Pt-Ir varnished tip. (c) EDS analysis of both as-received (red line) and graphene-coated (black line) tips. The insets in (c) show the SEM image for each tip. The scale bars are 3µm for as-received and 5µm for graphene-coated tips.