High resolution depth profiling using near-total-reflection hard X-ray photoelectron spectroscopy

TL;DR

This paper reviews a technique that uses near-total-reflection hard X-ray photoelectron spectroscopy to achieve high-resolution depth profiling of materials, especially for analyzing complex oxide heterostructures.

Contribution

It introduces the experimental setup, data analysis methods, and demonstrates broad applications, highlighting its capabilities for quantitative depth analysis in materials science.

Findings

Effective surface sensitivity tuning via X-ray incidence angle

Successful depth-resolved composition and electronic state analysis

Discussion of limitations in sample range applicability

Abstract

By adjusting the incidence angle of incoming X-ray near the critical angle of X-ray total reflection, the photoelectron intensity is strongly modulated due to the variation of X-ray penetration depth. Photoelectron spectroscopy (PES) combining with near total reflection (NTR) exhibit tunable surface sensitivity, providing depth-resolved information. In this review article, we first describe the experimental setup and specific data analysis process. We then review three different examples which show the broad application of this method. The emphasis is on its applications to correlated oxide heterostructures, especially quantitative depth analyses of compositions and electronic states. In a last part, we discussed the limitations of this technique, mostly in terms of range of samples which can be studied.