materiaux

Scientists make extensive use of X-ray fluorescence to map elements in materials. However, this technique does not have the needed spatial sensitivity unless the probe is finely focused.
Scientists have now found a way to turn X-ray fluorescence into an ultra-high position-sensitive probe to measure tiny internal structures called nanostructures in thin films (Nature Communications, “Reconstruction of Evolving Nanostructures in Ultrathin Films with X-ray Waveguide Fluorescence Holography”). These thin films can be a hundred times finer than a human hair.

Negative differential resistance (NDR), which describes a decrease in electrical current as the applied bias increases …