Research Group Materials Characterization and Nanomaterials
The aim of this group is the characterization of the optical, electrical and microstructural properties of thin layers and layer stacks predominantly for applications in solar cells.
The investigation of the microstructure of the films is, among others, based on lattice vibrations e.g. by Raman spectroscopy for the semi-quantitative determination of the crystalline volume fraction of microcrystalline films and on Infrared spectroscopy for the bonding of hydrogen. Analysis by Electron microscopy and X-Ray diffraction are additional methods which are used in collaboration with the IFF-IMF and IEF 2, respectively.
Besides classical methods the measurement of the optical properties of the sometimes very thin films is done by specially developed methods, e.g to determine very weak absorption for analysis of defects in the band gap. The investigation of the light scattering properties takes place on a macroscopic as well as on the sub-wavelength scale.
The transport and recombination of charge carriers are investigated with a broad spectrum of methods. The analysis involves single layers as well as devices, e.g. to extract parameters for device simulation.
As many of the experiments are not commercially available the development of new methods as well as the improvement of existing methods is an essential part of the research and development in the group.
New fields of activity are the development and utilization of nano-particles for new absorber layers and for absorption enhancement or light scattering based on plasmonic effects.