Neutron and X-ray reflectometry are key techniques for analyzing the nanoscale structure of thin films and interfaces, based on the principle of specular reflection – where the incident angle equals the reflection angle relative to the surface normal.

  • Specular Reflection: Central to both methods, it involves measuring the reflected beam’s intensity as a function of angle to deduce material properties.
  • Contrast Mechanisms: Neutrons are sensitive to isotopic differences, ideal for soft materials. X-rays respond to electron density contrasts, suitable for materials with high electron density variation.
  • Depth Profiling: These techniques offer depth profiles by evaluating reflectivity changes with angle, revealing layer thicknesses, interface roughness, and density gradients.
  • Critical Angle and Applications: The critical angle indicates total external reflection, linking to the material’s electron density or nuclear scattering length density. Applications span from thin film characterization and interface analysis to investigations in material science and biology, highlighting layer properties and interfacial dynamics.

Neutron and X-ray reflectometry provide detailed insights into material structures at the nanoscale, leveraging specular reflection to uncover information on layer thickness, density, and surface roughness.

A simple diagram of a reflectometry step up