Accurate mapping of nanoscale chemistry in three dimensions(3D)has been a longstanding challenge.Modern electron microscopy provides chemical images by electron energy loss spectroscopy(EELS)and energy dispersive x-ra...Accurate mapping of nanoscale chemistry in three dimensions(3D)has been a longstanding challenge.Modern electron microscopy provides chemical images by electron energy loss spectroscopy(EELS)and energy dispersive x-ray spectrometry(EDX)but requires high fluences that damage specimens.In 3D,the requirements are worse;electron tomography demands many highfluence chemical maps for reconstruction,creating a tradeoff between resolution,accuracy,and sample survival.Fused multimodal electron tomography(MM-ET)alleviates this requirement by leveraging lower-fluence high-angle annular dark-field(HAADF)images alongside a few chemical maps to dramatically improve chemical resolution.Here,experimental and computational parameter space is systematically explored to determine when MM-ET performs best.Ideal imaging conditions balance sample survival with resolution and chemical specificity;we recommend a tilt range of at least±70°,acquiring 40 equally spaced HAADF projections(signal-to-noise>10),and 7 EELS/EDX maps of each chemistry(signal-to-noise>4).展开更多
基金support from the U.S. Department of Energy, Basic Energy Sciences, under award DE-SC0024147J.M. acknowledges support from the National Science Foundation GRFPThis work used the Michigan Center for Materials Characterization (MC2), the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, and Argonne Leadership Computing Facility at Argonne National Laboratory, supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725 and DE-AC02-06CH11357. This research was supported in part through computational resources and services provided by Advanced Research Computing at the University of Michigan, Ann Arbor.
文摘Accurate mapping of nanoscale chemistry in three dimensions(3D)has been a longstanding challenge.Modern electron microscopy provides chemical images by electron energy loss spectroscopy(EELS)and energy dispersive x-ray spectrometry(EDX)but requires high fluences that damage specimens.In 3D,the requirements are worse;electron tomography demands many highfluence chemical maps for reconstruction,creating a tradeoff between resolution,accuracy,and sample survival.Fused multimodal electron tomography(MM-ET)alleviates this requirement by leveraging lower-fluence high-angle annular dark-field(HAADF)images alongside a few chemical maps to dramatically improve chemical resolution.Here,experimental and computational parameter space is systematically explored to determine when MM-ET performs best.Ideal imaging conditions balance sample survival with resolution and chemical specificity;we recommend a tilt range of at least±70°,acquiring 40 equally spaced HAADF projections(signal-to-noise>10),and 7 EELS/EDX maps of each chemistry(signal-to-noise>4).
