AG Jacobs

Atomic Force Microscopy (AFM)

Atomic force microscopy (AFM) is an experimental tool to investigate the topography and mechanical properties of a sample’s surface. Typically, the probe of an AFM is a microscopic, very sharp tip attached to a cantilever. The deflection of the cantilever, caused by the interaction between the tip and the sample surface can be measured via a laser and a photodiode. AFM therefore allows for quantitative topography measurements on the nanometer scale (even sub-nm in z-direction) as well as measurement of, e.g., adhesion force, Young’s modulus or friction. An AFM can be used in different environments, including liquids, and is therefore an excellent tool to investigate biological systems.
In our group, we use the following devices:

Bruker FastScan Bio
Bruker BioScope Catalyst

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Ultra High Vacuum Lab

X-ray photoelectron spectroscopy provides an experimental standard tool for surface analysis. It excels by its very high surface sensitivity, i.e., due to the very small electron mean free paths of electrons with kinetic energies in the range of 10–2000 eV (typically 1-2 nm) only the topmost layers of a sample are probed. Photoelectrons are detected in terms of their distribution of kinetic energies (as a measure of their binding energy) and their distribution of momentum with respect to, e.g., the crystal axes of the sample. In our group we use an

ESCALAB Mk II Photoelectron spectrometer

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Optical Microscopy

Optical microscopes use lens systems to magnify structures. Standard microscopes are limited in their resolution to the wavelength of visible light, i.e. a few 100 nm. We use light microscopes, for example, to observe the dewetting of thin films or to study the behaviour of protein layers and vesicles. Depending on the application, we use different microscopes, but primarily the following models

Leica DM2700M
Leitz Laborlux S