In practical surface electron spectroscopy, inelastic scattering of electrons is very important to understand because it is related to electron transport in solids. Thus, following the publication “How is the Signal Attenuation in Surface Electron Spectroscopy Described? I, II, and III”, I have described how to understand and calculate the practical inelastic scattering of electrons, how to take and convert units, how to express the average of the inelastic scattering, and the relationship between the optical (dipole) and generalized oscillator intensities.

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Photoelectron spectroscopy is a surface-sensitive method of measuring the chemical composition of materials. We have been utilizing this feature to study nanocarbon materials and two-dimensional materials, including graphene and hexagonal boron nitride (h-BN). In this paper, I will introduce our research results using photoelectron spectroscopy, which has revealed the band diagram of graphene/h-BN stacked structures and the gas barrier property of graphene,.

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We have been developing a vacuum electrospray droplet ion (V-EDI) beam technology using electrospray of aqueous solutions in vacuum. In order to effectively utilize the V-EDI beam as a probe for ionization and sputtering in secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS), the size and charge state of the droplet ions should be optimized. However, the characteristics of the droplet ions contained in the V-EDI beams have not been fully understood. In this study, the V-EDI beams were irradiated on a smooth polymer sample for a short time, and after that, its surface was analyzed with atomic force microscopy (AFM). When the inner diameter of a source capillary used for the V-EDI beams was changed in the range of 5 to 15 μm, the size and number distributions of the impact marks and the sputtered volumes calculated from those marks were drastically changed. From these results, valuable guidelines for effectively utilizing the V-EDI beams in surface analysis were obtained.

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“RIKEN KEIKI”, which manufactures the photoelectron yield spectrometers in air (AC series), has disclosed the format of the AC measurement data. In response, we have developed and released a conversion program written in Python to handle this data in our work. The program reads AC measurement format files and outputs measurement metadata, corrected measurement data, and manual analysis values in Excel or JSON format. A sample program that creates a list of metadata from the multiple files are attached as supplementary data. The output in Excel format can be used as a simple database, and that in JSON format can be used for database construction and web communication.

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LIB (Lithium Ion Battery) is used in various places such as mobile devices and electric vehicles. The battery performance of LIB is greatly influenced by SEI (Solid Electrolyte Interphase) coating formed on the negative electrode. It is known that the SEI coating is formed on the negative electrode in nanometer order thickness at the first time of charging. Though the SEI coating is indispensable for the charge and discharge of LIB, if the thickness of the SEI coating increases more than necessary, it leads to the lowering of the battery performance. Therefore, for further performance improvement of LIB, it is important to analyze the structure of SEI coating and to control its thickness. In this paper, a case of analyzing SEI coating formed on LIB negative electrode using laboratory HAXPES (Ag Lα) and conventional X-ray source (Al Kα) is introduced.

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