title: Diffractive electron imaging of nanoparticles on a substrate.
abstract: The observation of the detailed atomic arrangement within nanostructures has previously required the use of an electron microscope for imaging. The development of diffractive (lensless) imaging in X-ray science and electron microscopy using ab initio phase retrieval provides a promising tool for nanostructural characterization. We show that it is possible experimentally to reconstruct the atomic-resolution complex image (exit-face wavefunction) of a small particle lying on a thin carbon substrate from its electron microdiffraction pattern alone. We use a modified iterative charge-flipping algorithm and an estimate of the complex substrate image is subtracted at each iteration. The diffraction pattern is recorded using a parallel beam with a diameter of approximately 50 nm, illuminating a gold nanoparticle of approximately 13.6 nm diameter. Prior knowledge of the boundary of the object is not required. The method has the advantage that the reconstructed exit-face wavefunction is free of the aberrations of the objective lens normally used in the microscope, whereas resolution is limited only by thermal vibration and noise.
authors.affiliation: Department of Physics and Astronomy, Arizona State University, Tempe, Arizona 85287-1504, USA. jinsong.wu@asu.edu
authors.forename: Jinsong
authors.initials: J
authors.lastname: Wu
authors.forename: U
authors.initials: U
authors.lastname: Weierstall
authors.forename: John C H
authors.initials: JC
authors.lastname: Spence
mesh_terms: D000465:Algorithms; D002244:Carbon / Q000737:chemistry*; D004583:Electrons; D006046:Gold / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry; D036103:Nanotechnology; D013379:Substrate Specificity; D014961:X-Ray Diffraction
chemical_list: D002244:Carbon; D006046:Gold