Measurement of hardness, surface potential, and charge distribution with dynamic contact mode electrostatic force microscope

Dynamic contact mode electrostatic force microscopy (DC-EFM) was developed as a new operation mode of scanning probe microscope (SPM). By operating EFM in a contact mode with an ac modulation bias, we have improved the spatial resolution and also achieved a complete separation of the topographic effect from other electrostatic force effect overcoming the mixing problem of a topographic effect with other electrostatic effects frequently encountered in the conventional noncontact EFM measurement. DC-EFM can be utilized either as a force microscopy for the surface hardness, or as a potentiometry for the surface potential distribution, or as a charge densitometry for the surface charge density study. This is also applicable to the measurement and control of the domain structure in ferroelectric materials that have a bound surface charge.