Soft x-ray resonant reflectivity of low-Z material thin films

Abstract

Soft x-ray resonant reflectivity, a method for low-Z materials that combines aspects of neutron reflectivity and x-ray reflectivity, is presented. Resonant reflectivity provides enhanced and selective sensitivity to specific chemical moieties near the absorption edges of constituent elements and was demonstrated through the characterization of a bilayer polymer thin film. The relative reflectivity of a particular interface could be tuned by adjusting the incident photon energy near the carbon 1s absorption edge. The resulting chemical specificity is analogous to using deuteration as a tracer or marker in neutron reflectivity, but without requiring special sample synthesis or preparation.