Chemical State Mapping of p/n-Controlled SrB6 Bulk Specimens by Soft X-ray Emission Electron Microscope

Masami Terauchi,Yohei K Sato,Masatoshi Takeda

doi:10.3390/app11209588

Masami Terauchi, Yohei K Sato + Show 1 more

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https://doi.org/10.3390/app11209588

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Abstract

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.

Highlights

Recent developments in new functional materials, with the help of theoretical simulations and data science, could accelerate practical applications of these new functional materials
Electron-beam-induced X-ray emission was used for elemental analysis by using an X-ray energy dispersive spectroscopy (EDS) instrument, and elemental and partial chemical analyses were performed using an electron probe microanalyzer (EPMA)
As the energy spread of valence bands (VB) is smaller than 10 eV, an energy resolution better than 1 eV is necessary for obtaining information of chemical bonding states by soft X-ray emission spectroscopy (SXES)

Summary

Introduction

Recent developments in new functional materials, with the help of theoretical simulations and data science, could accelerate practical applications of these new functional materials. A soft X-ray emission spectroscopy (SXES) instrument, combined with a scanning electron microscope (SEM) and/or an electron probe microanalyzer (EPMA) can realize a nondestructive inspection process of the chemical state of materials, with a spatial resolution of about 1 μm or better [5,6,7]. If this occurs, SXES microscopy can make a quick feedback loop of the evaluated results of new products for materials processing

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Discussion

Conclusion