To tackle these challenges, a team from the National Institute for Materials Sciences (NIMS) and HORIBA Ltd, Japan, has developed a multiple-scanning-probe microscope (MSPM); a direct measurement tool for characterizing nano/micro conductors using two or more probes individually controlled in the manner of scanning probe microscopy.

A specially arranged tuning fork probe, which can be operated in vacuum, air and liquid environments, is used as a self-detection force sensor to operate the MSPM as an MSPFM, namely, in frequency modulation atomic force microscopy (AFM) mode.

Probing graphene

The group demonstrated simultaneous AFM imaging with four independent probes closely positioned around the same microscopic feature on the sample surface. Four-terminal electrical measurement is performed in air by placing each probe electrode in contact with a graphene flake exfoliated on a SiO2 film. The sheet resistance of the flake is then measured by the van der Pauw method.

The MSPFM has the potential to measure the intrinsic electrical properties of microscopic materials regardless of the conductivity of the substrate without using a scanning electron microscope.

The team's results provide a new approach to probing nano/micron-scale signal transfer in a wide range of materials in various environments, such as in ultrahigh vacuum, air and liquid.

More details can be found in the journal Nanotechnology.