Note: radiofrequency scanning probe microscopy using vertically oriented cantilevers

We present a simple method, based on the modification of a widespread atomic force microscope, that allows the simultaneous acquisition of the sample topography and RF spectra at the nanoscale minimizing the parasitic capacitance of the cantilever. We used a microcantilever set with its long axis perpendicular to the specimen surface and connected to a vector network analyzer (RF range 100 kHz-8.5 GHz) to measure RF impedance signal variations at the cantilever apex-sample interface. The RF impedance signal was found highly sensitive to very short probe-to-sample distances (<50 nm) and to material properties at the interface.