Electron spectro-microscopy of 2D materials

Miniaturization of electronic devices and progress in surface science demand novel, powerful microscopy methods for material characterization on a length scale of only a few atomic distances. This paper discusses application of the combined x-ray photoelectron microscopy / low-energy electron microscopy (XPEEM/LEEM) system to studying of the structural, electronic and chemical properties of surfaces at nanometer scale. Several examples are given, focusing on the comprehensive spectro-microscopic investigations of 2D structures, including epitaxially grown films as well as exfoliated, mu m-size thin flakes of 2D van der Waals materials. Benefitting from the high brilliance of the synchrotron, and utilizing its capabilities for in-situ sample preparation and treatment, the XPEEM/LEEM is a powerful tool for comprehensive characterization of static and dynamic properties of surfaces and interfaces, and it is particularly suited for comprehensive investigation of 2D materials, down to single monolayers.