Sub-Nanometer Depth Profiling of Native Metal Oxide Layers Within Single Fixed-Angle X-Ray Photoelectron Spectra.

Many metals form nanometer-thin self-passivating oxide layers upon exposure to the atmosphere, which affects a wide range of interfacial properties and shapes the way how metals interact with their environment. Such native oxide layers are commonly analyzed by X-ray photoelectron spectroscopy (XPS), which provides a depth-resolved chemical state and compositional analysis either by ion etching or modeling of the electron escape depths. The latter is commonly used to calculate the average thickness of a native oxide layer.