Chemical state mapping of p/n‐controlled SrB₆ bulk specimens by soft X‐ray emission electron microscope

Elemental and chemical state maps of p/n‐controlled SrB6 bulk specimens are presented by using a soft X‐ray emission spectroscopy electron microscope. Those bulk specimens were obtained by sintering powder specimens, prepared by the molten‐salt method with different compositions of initial materials. A Sr‐map, a chemical shift map of B K‐emission, and the spectra of characteristic regions of those materials were compared. It was observed that a local Sr deficiency caused a local hole‐doped region, confirmed by a chemical shift in the B K‐emission spectrum. n‐ type SrB6 was rather homogeneous. On the other hand, the p‐type SrB6 bulk specimen was a mixture of two different p‐type regions. This mixed nature originated, presumably, from an uneven Sr content of SrB6 particles prepared by the molten‐salt method using a Sr‐deficient starting material. A separation process of the two types of materials will realize a high‐quality homogeneous p‐type SrB6 bulk specimens.