Scanning Force Microscopy
With scanning force microscopy we investigating surfaces with atomic resolution. Beside topography, specific operating modes and probes can be used to characterize lateral variations of frictional, elastic, thermal, and electrical material properties. Kelvin probe force microscopy (KPFM), for example, measures the electrical potential under the tip. Thereby, work function variations across the sample surface can be mapped with 10 nm lateral and 10 mV voltage resolution. In photovoltaic materials, light-induced changes in the measured surface potential are associated to charge transport across interfaces. In combination with infrared light (IR) illumination, we record local IR spectra with a lateral resolution <50 nm. The use of this nano-IR method allows us to locally detect the presence of chemical species in samples. The latter technique can be used for polymer blends, block-copolymers etc.