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In this study, we report the application of synchrotron radiation microprobe to the analysis of Mn-rich clusters in GaN. From the Mn and Ga fluorescence line intensity ratio, an average Mn concentration of 11% was deduced. A combination of fluorescence mapping with spectroscopic techniques enabled us to examine not only the cluster elemental nature but also their crystallographic orientation on the submicron scale. The strong polarization-dependent x-ray absorption near-edge structure features showed the preservation of the hexagonal symmetry in both cluster-free and Mn-rich regions. However, from the x-ray absorption data taken inside the clusters, a preferential disorder was observed in the direction parallel to the crystal growth rather than perpendicular to it.

The local prebreakdown behavior of a damage etched multicrystalline silicon solar cell produced from virgin grade feedstock was characterized. At the position of micrometer-scaled prebreakdown sites, which correlate with recombination active defects found along grain boundaries, micro-x-ray fluorescence mappings revealed the presence of Fe precipitate colonies. These measurements represent direct evidence that transition metal clusters lead to decreased breakdown voltage and cause soft diode breakdown

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