title: Novel silica stabilization method for the analysis of fine nanocrystals using coherent X-ray diffraction imaging.
abstract: High-energy X-ray Bragg coherent diffraction imaging (BCDI) is a well established synchrotron-based technique used to quantitatively reconstruct the three-dimensional morphology and strain distribution in nanocrystals. The BCDI technique has become a powerful analytical tool for quantitative investigations of nanocrystals, nanotubes, nanorods and more recently biological systems. BCDI has however typically failed for fine nanocrystals in sub-100 nm size regimes - a size routinely achievable by chemical synthesis - despite the spatial resolution of the BCDI technique being 20-30 nm. The limitations of this technique arise from the movement of nanocrystals under illumination by the highly coherent beam, which prevents full diffraction data sets from being acquired. A solution is provided here to overcome this problem and extend the size limit of the BCDI technique, through the design of a novel stabilization method by embedding the fine nanocrystals into a silica matrix. Chemically synthesized FePt nanocrystals of maximum dimension 20 nm and AuPd nanocrystals in the size range 60-65 nm were investigated with BCDI measurement at beamline 34-ID-C of the APS, Argonne National Laboratory. Novel experimental methodologies to elucidate the presence of strain in fine nanocrystals are a necessary pre-requisite in order to better understand strain profiles in engineered nanocrystals for novel device development.
authors.affiliation: London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Marianne
authors.initials: M
authors.lastname: Monteforte
authors.affiliation: London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Ana K
authors.initials: AK
authors.lastname: Estandarte
authors.affiliation: London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Bo
authors.initials: B
authors.lastname: Chen
authors.affiliation: Argonne National Laboratory, Advanced Photon Source, Argonne, IL 60439, USA.
authors.forename: Ross
authors.initials: R
authors.lastname: Harder
authors.affiliation: National Tsing Hua University, Guangfu Rd, East District, Hsinchu City 300, Taiwan.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Huang
authors.affiliation: London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Ian K
authors.initials: IK
authors.lastname: Robinson
keywords: Bragg coherent X-ray diffraction; nanocrystals; stabilization method; strain; three-dimensional reconstruction