Development of Spatiotemporal Measurement and Analysis Techniques in X-ray Photoelectron Spectroscopy ∼From NAP-HARPES to 4D-XPS∼

We have developed spatiotemporal measurement and analysis techniques in x-ray photoelectron spectroscopy. To begin with, time-division depth profiles of gate stacked film interfaces have been achieved by NAP-HARPES (Near Ambient Pressure Hard x-ray Angle-Resolved PhotoEmission Spectroscopy) data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division ARPES data, which enables us to realize 4D-XPS analysis. It is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling in NAP-HARPES data is effective to perform dynamic measurement of depth profiles with high precision.