Matthias Müller, Scientist at Physikalisch-Technischn, Bundesanstalt (PTB), Berlin, Germany
Advanced research on novel semiconductor, energy-storage and energy-conversion devices relies on the reliability of the characterization of material systems of interest. In particular, standard-less and non-destructive analytical methods are to be employed. X-Ray Fluorescence (XRF) analysis has proven to be a reliable and promising method for material characterization. In general, this method relies on standard samples or reference materials for calibration purposes, which can severely restrict its applicability when dealing with new materials with missing or inappropriate reference samples. The use of a Fundamental Parameter (FP) based quantification method can help to overcome these calibration restrictions. The reliability of the FP quantification depends on the quality of the FP data available, which is actually not good enough for relevant applications such as nanolayer analyses in the soft x-ray range.
Nowadays, High-resolution X-ray Emission Spectroscopy (XES) employing synchrotron radiation allows for more detailed studies of the interaction of x-rays with matter. In combination with calibrated instrumentation, XES can be used to determine FPs for elements present in novel material systems. In PTB's laboratory at the electron storage ring BESSY II calibrated instrumentation such as a wavelength-dispersive grating spectrometer was used to determine FPs related to the L fluorescence emission of transition metals by means of XES measurements [1]. In addition to the improvement of the reliability of FP databases, this kind of studies has the potential to increase our knowledge about the interaction of x-rays and matter, e.g. regarding satellite emissions, cascade effects and chemical state effects on the fluorescence cross sections.
[1] M. Müller, B. Beckhoff, R. Fliegauf, and B. Kanngießer, Phys. Rev. A, 79, 032503 (2009).
