KPFM operates by using a conductive AFM tip which hovers above the sample surface. A voltage is applied between the tip and the sample, generating an electrostatic force. The system then adjusts the applied voltage to nullify this force, effectively measuring the CPD. This process involves two major steps:
1. Feedback Loop: A feedback mechanism adjusts the bias voltage applied to the tip to nullify the electrostatic force, thus identifying the CPD. 2. Topography and Potential Imaging: The AFM tip scans the surface topography in tapping mode, while simultaneously measuring the local CPD to generate a potential map.
