Surface potential measurements by the dissipative force modulation method

In this study, we propose a novel surface property measurement technique using noncontact atomic force microscopy (NC-AFM), which is referred to as the “dissipative force modulation (DM) method.” NC-AFM-based surface property measurements have mostly utilized conservative tip-sample interaction forces, which induce a frequency shift of cantilever resonance without dissipating cantilever vibration energy. In the DM method, local surface properties are measured by detecting a modulated dissipative tip–sample interaction force which dissipates cantilever vibration energy and hence induces an amplitude variation in cantilever vibration. Since the force sensitivity to dissipative interactions obtained in a typical NC-AFM setup is much higher than that to conservative ones, the DM method can improve the sensitivities of conventional NC-AFM-based techniques that utilize conservative interactions. Combining this method with Kelvin-probe force microscopy, we present the first quantitative surface potential measurement through dissipative tip–sample interactions.