X-ray Scattering & X-ray Diffraction

Research at LAS concentrates on the characterisation of thin films, interfaces and nanostructures using X-ray scattering techniques. Such materials play an important role in modern technology  – layers of only a few nanometers thickness form the basis of state-of-the-art high-density integrated chip fabrication, while thin films of materials such as carbides or nitrides, with thicknesses of only several 10s of nanometers, provide corrosion and temperature resistance for mechanical structures such as aircraft turbine blades.                                          

Of special interest is the elucidation of nanoscale structural information during materials processing, for example:

• in situ observation of structure formation during growth processes
• operando analysis of material processing/cycling
• multi-scale resolution (atomic to nanoscale, correlation to macroscale) and methodical combination

For the characterisation of such materials LAS employs a range of experimental synchrotron-based methods such as:

• High-resolution X-ray diffraction (HRXRD)
• X-ray Reflection (XRR)
• Grazing-incidence small-angle scattering (GISAXS)
• Grazing incidence X-ray diffraction (GID)
• Reciprocal Space Mapping   

both at the KIT Synchrotron source and at other leading synchrotron sources.

A. Seiler, S. Ibrahimkutty, P. Wochner, R. Pradip, O. Waller, et al., Thermal Stability Studies of DySi2 Nanowires and Nanoislands by In Situ GISAXS, J. Phys. Chem. C 120 (2016) 7365 – 7372.

Example: Application of asymmetric skew X-ray diffraction to semiconductor nano-objects

Procedures for obtaining three-dimensionally resolved reciprocal-space maps in skew X-ray diffraction geometry allow tuning of the information depth in the range from tens of micrometres for symmetric skew diffraction down to tens of nanometres for strongly asymmetric skew geometries, where the angle of incidence is below the critical angle of total external reflection.