Determination of Sign of Surface Charges of Ferroelectric TGS Using Electrostatic Force Microscope Combined with the Voltage Modulation Technique

Abstract

The sign of surface charges and the surface topography around a domain wall on a cleaved (010) surface of ferroelectric TGS [ (NH2CH2COOH)3·H2SO4] were studied in air at room temperature. Using an electrostatic force microscope (EFM) combined with the voltage modulation technique, we determined the location of the domain wall and the sign of the surface charges around it. At the domain wall, we found a ridge structure with a large peak in the spatial distribution of a feedback signal used to keep the amplitude of the 2ω component of electric force constant. This means that the dielectric constant has a large peak value at the domain wall. Furthermore, in an atomic force microscope (AFM) image in a contact mode, we observed a small step 2–3 Å high at the center of the domain wall.