Microscopy
Scanning Electronen Microscope (SEM)
The basic principle of SEM (scanning electron microscope) is that an electron beam is positioned on the sample, and interactions lead to different types of electrons and photons being emitted from the sample, which are detected. The working group Mathur has a FEI Nova NanoSEM 430 at its disposal which is used for analyzing topographical properties of samples of thin films, nanofibers, nanoparticles, functional surfaces, coatings for bio-medical applications and many more. For determining the elemental composition of the sample an EDX (energy dispersive X-Ray spectroscopy) detector is integrated in the machine. Furthermore, access to other electron microscopes of the Departmen of Chemistry is granted through the service platform for electron microscopy. Please check the platforms' webpage for more information about the available instruments and measurement techniques.
Transmission Electron Microscope (TEM)
The group has access to a JEOL JEM-2200FS by the TEM-Usergroup Cologne. The TEM is placed in the institute for inorganic chemistry.
Scanning Probe Microscopy
The Scanning Probe Microscope (SPM, Park Systems XE series) plays an important role for exploring the world of nano technology by offering surface imaging of the measured samples at atomic level. On one hand, based on quantum tunnelling, the Scanning Tunnelling Microscope (STM) records every change of the tunnelling current between the probe tip and the sample surface in a vacuum state. Since the tunnelling current is a function of tip position and local density of states of the sample surface, surface topography information can be then acquired as the tip scans over an area of the sample. Nevertheless, STM measurements are limited to those samples which are conducting or semiconducting. On the other hand, Atomic Force Microscope (AFM) provide a whole new range of measurement capabilities. With the cantilever scanning over sample surfaces, either in contact or non-contact with the surface, the AFM monitors the displace of the cantilever with the help of a piezoelectric element with high accuracy and precision. It is not limited to electrical conducting materials. Furthermore, depending on the demand of the users and specific sample properties, it is able to perform such measurements that reveal physical, chemical, mechanical, electrical and magnetic properties of the sample surface.