Probing electrical transport properties at the nanoscale by Current-Sensing atomic force microscopy

In this chapter, we review the fundamentals and recent advances of current-sensing atomic forcemicroscopy (CS-AFM) with particular emphasis on instrumental aspects. After discussing some generic aspects concerning themeasurement of electrical currents at the nanoscale, we review the main CS-AFM techniques developed to probe the electrical transport properties at the nanoscale, namely, conductive atomic force microscopy, nanoscale impedance microscopy and electron noise microscopy. In each case we describe the electronic instrumentation implemented and the main applications of the technique to the fields of material science, electronics and biology. It is concluded that the measurement of direct and alternating currents and of current fluctuations with nanoscale spatial resolution provides an invaluable tool for an understanding of the spatially resolved electrical transport properties at the nanoscale.