scanning kelvin probe

**Scanning Kelvin Probe** is an **extension of the Kelvin Probe technique that creates spatial maps of surface potential or work function** — either as a macroscopic scanning system or as an AFM-based technique (KPFM/SKP-AFM) with nanometer spatial resolution. **Two Main Implementations** - **Macroscopic SKP**: A vibrating probe (~100 μm - 1 mm diameter) scanned over the surface. Resolution ~50-100 μm. - **KPFM (Kelvin Probe Force Microscopy)**: AFM-based. AC bias modulates the electrostatic force. Resolution ~20-50 nm. - **FM-KPFM**: Frequency modulation mode provides higher spatial resolution than AM-KPFM. - **HD-KPFM**: Heterodyne detection for improved sensitivity. **Why It Matters** - **Corrosion**: Maps Volta potential differences between phases to predict galvanic corrosion. - **Semiconductor**: Maps dopant contrast, p-n junctions, and contact potential at device surfaces. - **Solar Cells**: Visualizes charge accumulation and grain boundary potentials in polycrystalline solar cells. **Scanning Kelvin Probe** is **the surface potential camera** — creating maps of work function or surface potential at micro to nanometer resolution.