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Title Kuchibhatla, Satyanarayana V. N. T.; Shutthanandan, V; Prosa, T. J.; Adusumilli, P.; Arey, B.; Buxbaum, A.; Wang, Y. C.; Tessner, T.; Ulfig, R.; Wang, C. M.; Thevuthasan, S.
Year Three-dimensional chemical imaging of embedded nanoparticles using atom probe tomography
Abbreviated Journal Journal Article
Issue 2012 Keywords Nanotechnology
Thesis 23
Place of Publication 21 Language 215704
Original Title
Series Title Analysis of nanoparticles is often challenging especially when they are embedded in a matrix. Hence, we have used laser-assisted atom probe tomography (APT) to analyze the Au nanoclusters synthesized in situ using ion-beam implantation in a single crystal MgO matrix. APT analysis along with scanning transmission electron microscopy and energy dispersive spectroscopy (STEM-EDX) indicated that the nanoparticles have an average size ~ 8-12 nm. While it is difficult to analyze the composition of individual nanoparticles using STEM, APT analysis can give three-dimensional compositions of the same. It was shown that the maximum Au concentration in the nanoparticles increases with increasing particle size, with a maximum Au concentration of up to 50%. Series Volume
Serial (down) Orig Record
0957-4484 no NU @ karnesky @ 11355
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Mao, Zugang; Kim, Yeong-Cheol; Lee, Hi-Deok; Adusumilli, Praneet; Seidman, David N. NiSi crystal structure, site preference, and partitioning behavior of palladium in NiSi(Pd)/Si(100) thin films: Experiments and calculations Journal Article 2011 Applied Physics Letters 99 1 013106 ab initio calculations; crystal structure; metallic thin films; nickel alloys; palladium alloys; silicon alloys; tomography; X-ray diffraction The crystal structure of a NiSi thin-film on a Si substrate and Pd site-substitution in NiSi and the partitioning behavior of Pd for NiSi(Pd)/Si(100) are investigated by x-ray diffraction (XRD), first-principles calculations, and atom-probe tomography (APT). The NiSi layer is a distorted orthorhombic structure from XRD patterns via experiments and calculations. We find that Pd has a strong driving force, 0.72 eV atom−1, for partitioning from Si into the orthorhombic NiSi layer. The calculated substitutional energies of Pd in NiSi indicate that Pd has a strong preference for Ni sublattice-sites, which is in agreement with concentration profiles determined by APT. Aip 0003-6951 no NU @ karnesky @ ref10.1063/1.3606536 11169
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Kuchibhatla, Satyanarayana, V. N. T.; Adusumilli, P.; Prosa, T. J.; Ulfig, R. M.; Shutthanandan, V.; Arey, B. W.; Thevuthasan, S. Influence of embedded Au-nanoclusters on the Atom Probe Tomography of Bulk MgO Abstract 2010 Advances in Optical and Electron Microscopy, Vol. 2, R. Barer and V. E. Cosslett, eds., Academic Press, London (1968) 343analysis The advent of laser-pulsing in atom probe tomography (APT) has significantly expanded the scope of this high spatial resolution, three-dimensional analysis technique to study insulating materials such as oxides. Recent first-of-their-kind studies on bulk insulating magnesium oxide single crystal substrates, with and without embedded gold nanoparticles, have revealed some very interesting information. This presentation will include some of these results describing the influence of laser energy on the field evaporation characteristics of pure and Au clusters imbedded MgO specimens during laser-assisted APT. The Au clusters imbedded specimens were prepared by implanting 2.0 MeV 2x1017 Au+/cm2 in bulk MgO crystals at various temperatures and subsequently annealing the specimens at 1000oC for 10 hours in air. Samples for APT were prepared using a dual-beam focused ion beam microscope using the lift-out technique. Significant variations have been observed in the mass resolution and the TOF-mass spectrum as a function of the presence of nanoclusters in the oxide matrix. While the average dimensions of the gold nanoparticles in the matrix agree with the TEM and STEM measurements, APT data indicates that the Au-clusters may not be pure as reported by researchers in the past. Furthermore, using atom-probe reconstructions, (see Figures 1 and 2 below), the presentation will shed light on the different evaporation characteristics observed at high and low laser energies. Additionally, the influence of laser energy and Au nanoparticle presence on the bulk composition will also be discussed here. While it is too early to make conclusive propositions on the Au-MgO system, these results are highly encouraging to pursue the analysis of bulk insulators and dielectric materials using laser assisted atom probe tomography. It is being hypothesized that the selective absorption of the laser by the Au nanoparticles might result in localized heating and there by result in magnesium oxide clustering in the vicinity of Au clusters. MgO clustering effects appear to depend on the laser energy and the results clearly demonstrate that complex MgO clustering can be avoided by utilizing low laser energies as shown in Fig. 1. no NU @ karnesky @ 10870
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Thevuthasan, S.; Kuchibhatla, Satyanarayana, V. N. T.; Adusumilli, P.; Olszta, M.; Arey, B.; Shutthanandan, V.; McKinely, J. P.; Wang, C. M.; Bruemmer, S.; Baer, D. R.; Prosa, T.; Ulfig, R.; Seidman, D.; Buxbaum, A.; Wang, Y. C.; Tessner, T. Laser Assisted Atom Probe Tomography analysis of nanoscale, energy and environment related materials at EMSL Abstract 2010 Microscopy and Microanalysis Increasing emphasis on materials with enhanced properties in various functional applications has provided an impetus to develop the tools that will help understand materials with increased spatial resolution, at larger field-of-view and enhanced sensitivity. Laser assisted atom probe tomography analysis fits these objectives well and provides 3D-chemical images. While the atom probe analysis has been used for a few decades, the development of laser pulsing has extended the scope of this technique from metals to semiconductors and very recently to the insulating materials such as bulk oxides. EMSL, a national scientific user facility of the DOE, is developing an atom probe tomography capability complimenting the existing surface and interfacial analysis, microscopy capabilities to provide solutions to various problems of interest to energy and environment, in particular, at the nanoscale. This presentation examines the feasibility of using atom probe for various challenging materials systems including some that have not been previously examined by atom probe methods. We report the first Local Electrode Atom Probe (LEAP®) analysis of Au nanoparticles embedded in MgO using ion beam synthesis method, in which, 2MeVAu ions were implanted in a MgO(100) substrate at various temperatures and the substrate was subsequently annealed at 1000oC for 10 hours in air. These samples were analyzed using a combination of atom probe tomography and analytical electron microscopy. Also analyzed for the first time, are the samples obtained from the reductive biotransformation of 6-line ferrihydrite located within porous silica (intragrain ferrihydrite) by Shewanella oneidensis MR-1. Imaging and analysis of biologically induced Fe- phosphate precipitates in porous silica using He-ion microscopy and atom probe tomography will be outlined. Selected results from EMSL user projects related to semiconductor and nuclear energy materials will also be discussed. Dopant distribution and the oxidation mechanisms will be predicted based on the atom probe analysis in these systems. Dual beam FIB/SEM systems at EMSL have been extensively used for sample preparations and some of the key observations during sample preparations will also be outlined in this presentation. no NU @ karnesky @ 10869
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Adusumilli, Praneet; Murray, Conal E.; Lauhon, Lincoln J.; Avayu, Ori; Rosenwaks, Yossi; Seidman, David N. Three-Dimensional Atom-Probe Tomographic Studies of Nickel Monosilicide/Silicon Interfaces on a Subnanometer Scale Journal Article 2009 ECS Transactions ECST 19 1 303-314 Three-dimensional atom-probe tomography was utilized to study the distribution of M (M = Pt or Pd) after silicidation of a solid-solution Ni0.95M0.05 thin-film on Si(100). Both Pt and Pd segregate at the (Ni1-xMx)Si/Si(100) heterophase interface and may be responsible for the increased resistance of (Ni1-xMx)Si to agglomeration at elevated temperatures. Direct evidence of Pt short-circuit diffusion via grain boundaries, Harrison regime-B, is found after silicidation to form (Ni0.99Pt0.01)Si. This underscores the importance of interfacial phenomena in stabilizing this low-resistivity phase, providing insights into the modification of NiSi texture, grain size, and morphology caused by Pt. The relative shift in work function between as-deposited and annealed states is greater for Ni(Pt)Si than for NiSi as determined by Kelvin probe force-microscopy. The nickel monosilicide/Si heterophase interface is reconstructed in three-dimensions and its chemical roughness is evaluated. yes NU @ praneet @ 10693
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Adusumilli, Praneet; Lauhon, Lincoln J.; Seidman, David N.; Murray, Conal E.; Avayu, Ori; Rosenwaks, Yossi Tomographic study of atomic-scale redistribution of platinum during the silicidation of Ni0.95Pt0.05/Si(100) thin films Journal Article 2009 Applied Physics Letters APL 94 11 113103_1-3 annealing, atom probe field ion microscopy, elemental semiconductors, grain boundaries, grain size, nickel alloys, platinum, semiconductor-metal boundaries, silicon, surface diffusion, surface texture, surface topography, thin films, work function Atom-probe tomography was utilized to study the distribution of Pt after silicidation of a solid-solution Ni0.95Pt0.05 thin film on Si(100). Direct evidence of Pt short-circuit diffusion via grain boundaries, Harrison's type-B regime, is found after silicidation to form (Ni0.99Pt0.01)Si. This underscores the importance of interfacial phenomena for stabilizing this low-resistivity phase, providing insights into the modification of NiSi texture, grain size, and morphology caused by Pt. Platinum segregates at the (Ni0.99Pt0.01)Si/Si(100) interface, which may be responsible for the increased resistance of (Ni0.99Pt0.01)Si to agglomeration. The relative shift in work function between as-deposited and annealed states is greater for Ni(Pt)Si than for NiSi. Northwestern Univ, Dept Mat Sci & Engn, 2220 Campus Dr, Evanston, IL 60208 USA AMER INST PHYSICS, CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA 0003-6951 yes NU @ praneet @ 10692
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Lauhon, Lincoln J.; Adusumilli, Praneet; Ronsheim, Paul; Flaitz, Philip L.; Lawrence, Dan Atom-Probe Tomography of Semiconductor Materials and Device Structures Journal Article 2009 MRS Bulletin 34 10 738-743 The development of laser-assisted atom-probe tomography (APT) analysis and new sample preparation approaches have led to significant advances in the characterization of semiconductor materials and device structures by APT. The high chemical sensitivity and three-dimensional spatial resolution of APT makes it uniquely capable of addressing challenges resulting from the continued shrinking of semiconductor device dimensions, the integration of new materials and interfaces, and the optimization of evolving fabrication processes. Particularly pressing concerns include the variability in device performance due to discrete impurity atom distributions, the phase and interface stability in contacts and gate dielectrics, and the validation of simulations of impurity diffusion. This overview of APT of semiconductors features research on metal-silicide contact formation and phase control, silicon field-effect transistors, and silicon and germanium nanowires. Work on silicide contacts to silicon is reviewed to demonstrate impurity characterization in small volumes and indicate how APT can facilitate defect mitigation and process optimization. Impurity contour analysis of a pFET semiconductor demonstrates the site-specificity that is achievable with current APTs and highlights complex device challenges that can be uniquely addressed. Finally, research on semiconducting nanowires and nanowire heterostructures demonstrates the potential for analysis of materials derived from bottom-up synthesis methods. no NU @ karnesky @ 10683
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Kim, Y.-C.; Adusumilli, P.; Lauhon, L.J.; Seidman, D.N.; Jung, S.-Y.; Lee, H.-D.; Alvis, R.L.; Ulfig, R.M.; Olson, J.D. Three-dimensional atomic-scale mapping of Pd in Ni[sub:1 - x]Pd[sub:x]Si/Si(100) thin films Journal Article 2007 Applied Physics Letters Appl. Phys. Lett. 91 11 113106:1-3 annealing; interface roughness; nickel compounds; palladium compounds; rapid thermal processing; semiconductor-metal boundaries Atom-probe tomography was utilized to map the three-dimensional distribution of Pd atoms in nickel monosilicide thin films on Si(100). A solid-solution Ni0.95Pd0.05 film on a Si(100) substrate was subjected to rapid thermal processing plus steady-state annealing to simulate the thermal processing experienced by NiSi source and drain contacts in standard complementary metal-oxide-semiconductor processes. Pd is found to segregate at the (Ni0.95Pd0.05)Si/Si(100) heterophase interface, which may provide a previously unrecognized contribution to monosilicide stabilization. The silicide-Si heterophase interface was reconstructed in three dimensions on an atomic scale and its chemical roughness was evaluated. Aip no NU @ karnesky @ 9944
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