Atomic force microscope based Kelvin measurements: Application to an electrochemical reaction

An atomic force microscope (AFM) was utilized as a Kelvin probe to determine work functions of several metals and semiconductors quantitatively. Most of the experimental data show excellent agreement with published values measured by photoemission, Variations in work functions as low as 5 mV could be detected with a typical lateral resolution of 20 nm. This method allowed us to analyze and explain the energetics of an electrochemical reaction on the surface of WSe2, which could be in situ induced and controlled by an externally applied voltage between AFM tip and sample. Thus it could be exploited for etching nanostructures.