Abstract
Electric force microscopy (EFM) and Kelvin probe force microscopy (KFM) have been widely used for studying electrical properties of nanometer-scale structures. Since they were invented at the early stage of atomic force microscopy (AFM) history, both techniques have been drastically developed with dynamic-mode AFM, where the cantilever is used as a mechanical oscillator. They are capable of mapping local work function and electronic states of a wide variety of material surfaces on an atomic/molecular scale. Here in this article we review the present status of EFM and KFM mainly based on frequency modulation AFM and discuss the future prospects.
