New Capabilities of NT-MDT AFM Microscopes: Single-pass Electrostatic Measurements

The stationary solutions of the asymptotic equation describing the force interactions between an oscillatory probe and a sample provide the relationship between the probe parameters (amplitude A, phase θ, position Zc) and the acting force (cos θ ≈ FZ). Under the assumption of small amplitude cos θ is proportional to the force gradient. However, we go beyond this assumption by expressing the integral in its simple closed form [2]. Advanced studies of surface potential and dielectric response were performed using single-pass measurement operation with an NT-MDT atomic force microscope (AFM) equipped with a novel electronic controller that allows multi-frequency AFM studies. Sensitive measurements of local electrical properties, with a few nanometers spatial resolution, were realized in practice through phase modulation detection of the electrostatic force gradient. The validity of this approach is demonstrated on several different sample types: