Fast Multifrequency Measurement of Nonlinear Conductance

Measuring small currents and mapping nonlinear electrical properties are key to characterizing modern devices and investigating physics at the nanoscale. Here the high capacitance and low conductance of nanojunctions limit measurement speed. The authors introduce a multifrequency technique to separate Galvanic and displacement currents, and to compensate for parasitic contributions, achieving a speedup of four orders of magnitude when measuring current-voltage characteristics with a conductive atomic force microscope. This flexible approach for fast, high-resolution electrical characterization in nanotechnology is also directly applicable to scanning tunneling microscopy.