Atomic Structure Imaging in ZnSe and Mixed Zn0.74Mn0.2Be0.06Se Crystals with X-ray Fluorescence Holography.

X-ray fluorescence holograms of ZnSe and Zn_0.74Mn_0.2Be_0.06Se single crystals were measured by means of a table-top laboratory setup. Holograms were recorded simultaneously for Zn K, Se K and, in the case of the mixed crystal, for Mn K X-ray fluorescence. Analysis of the holograms was based on a linear regression algorithm preceded by the matrix effects correction. It enabled the determination of real and imaginary parts of the structure factors from which atomic structures around different fluorescing atoms could be reconstructed. In particular, direct imaging of Mn lattice sites in Zn_0.74Mn_0.2Be_0.06Se unambiguously demonstrated that the majority of Mn atoms occupy substitutional Zn positions. However, it was shown that the precise analysis of Mn lattice site distribution can be hindered due to extinction effects which have to be included in the analysis of XFH in the case of non-centrosymmetric samples. [ABSTRACT FROM AUTHOR]