Low-dimensional systems investigated by x-ray absorption spectroscopy: a selection of 2D, 1D and 0D cases

Abstract

During the last three decades low dimensional systems attracted increasing interest both from the fundamental and the technological point of view due to their unique physical and chemical properties.X-ray Absorption Spectroscopy (XAS) is a powerful tool for the characterization of such kind of systems, owing to its chemical selectivity and high sensitivity in interatomic distances determination.Moreover this technique can simultaneously provide information on electronic and local structural properties of the nanomaterials, significantly contributing to clarify the relation between their atomic structure and their peculiar physical properties.This review provides a general introduction to XAS, discussing the basic theory of the technique, the most used detection modes, the related experimental setups and some complementary relevant characterization techniques (DAFS, EXELFS, PDF, XES, HERFD XAS, XRS).Subsequently a selection of significant applications of XAS spectroscopy to 2D, 1D and 0D systems will be presented.The selected low dimensional systems include IV and III-V semiconductor films, quantum wells, quantum wires and quantum dots; carbon based nanomaterials (epitaxial graphene and carbon nanotubes); metal oxide films, nanowires, nanorods and nanocrystals; metal nanoparticles.Finally, the future perspectives for the application of XAS to nanostructures are discussed.