Optically Detected X-ray absorption spectroscopy (OD-XAS)

Optically Detected X-ray ray absorption spectroscopy (OD-XAS) is one of the few methods available for directly linking the optical and structural properties of matter. It is useful for probing both the bulk atoms of a solid, and defects contained within them.

OD-XAS works best on luminescent semiconductors and insulators, whose band-gaps vary from 0.5 to 10eV. All the standard structural XAS information is available when scanning the excitation over the core-levels of the atom of interest, so the method works over a wide excitation energy range from ~10eV to >70keV. But the signals are monitored by detecting changes in the luminescence emission intensity of the samples and this can typically be in the range 0.7 to 7eV. Ideally, the emission is wavelength resolved, allowing the relationship between structure and luminescence of different emission systems to be probed.

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