Quantitative 3D Imaging of Nanostructured Materials by Using Coherent X-Rays
Jianwei Miao
Department of Physics and Astronomy and the Californis Nanosystems Institute, University of California at Los Angeles
Because X-rays have a longer penetration depth than electrons and X-ray wavelengths are on the order of the size of atoms, there exists the prospect for atomic-resolution X-ray microscopes that could visualize arrangement and dynamics of atoms in three dimensions - without the requirement for periodicity (e.g. crystals). X-rays, however, are much more difficult to focus than electrons. By using Fresnel zone plates, the smallest focal spot currently achievable is 30 nm for hard X-rays and 15 nm for soft-X-rays. With 3rd generation synchrotron radiation, we have developed a lensless microscope, which is based upon coherent X-ray scattering in combination with a method of direct phase recovery called oversampling. By using this novel X-ray microscope, we have investigated nanostructured materials in three dimensions. Our work opens a door for non-destructive and quantitative imaging of 3D morphology and 3D internal structures of a wide range of samples including porous materials, semiconductors, quantum dots and wires, inorganic nanostructures and biomaterials at the nanometer level.
