A5070504241- Microstructure and mechanical properties
- Advanced Electron Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Metal and Thin Film Mechanics
- Copper Interconnects and Reliability
- Semiconductor materials and devices
- Aluminum Alloy Microstructure Properties
- Force Microscopy Techniques and Applications
- Electronic and Structural Properties of Oxides
- Surface Roughness and Optical Measurements
- Aluminum Alloys Composites Properties
- Advanced Memory and Neural Computing
- X-ray Diffraction in Crystallography
- Advanced X-ray Imaging Techniques
- Advanced Surface Polishing Techniques
- Advanced Materials Characterization Techniques
- Anodic Oxide Films and Nanostructures
- Surface and Thin Film Phenomena
- Photonic Crystals and Applications
- Advancements in Solid Oxide Fuel Cells
- Hydrogen embrittlement and corrosion behaviors in metals
- Fusion materials and technologies
- Optical measurement and interference techniques
- Metallurgy and Material Forming
- Phytoplasmas and Hemiptera pathogens
Rio Salado College
2012-2019
TechnoServe
2014-2017
Carnegie Mellon University
2009-2016
Oxford Instruments (Canada)
2014
Abstract Nanotendril “fuzz” will grow under He bombardment tokamak-relevant conditions on tungsten plasma-facing materials in a magnetic fusion energy device. We have grown nanotendrils at low (50 eV) and high (12 keV) energy, the range 900–1000 °C, characterized them using electron microscopy. Low tendrils are finer (~22 nm diameter) than high-energy (~176 diameter), low-energy smoother surface tendrils. Cavities were omnipresent typically ~5–10 size. Oxygen was present tendril surfaces,...
Sputter-deposited W films with nominal thicknesses between 5 and 180 nm were prepared by varying the base pressure prior to film deposition including or not sputtered SiO2 encapsulation layers. X-ray electron diffraction studies showed that single phase, polycrystalline α-W could be achieved in as-deposited as thin nm. The stress state was found inhomogeneous. Annealing resulted relaxation reduction of resistivity for all films, except thinnest, unencapsulated film, which agglomerated....
The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account twin-boundary scattering. It has been difficult quantitatively assess impact twin boundary scattering on classical size effect electrical resistivity, due limitations characterizing boundaries Cu. In this study, crystal orientation maps films obtained via precession-assisted electron diffraction transmission microscope. These images used...
Abstract Stereological analysis has been coupled with transmission electron microscope (TEM) orientation mapping to investigate the grain boundary character distribution in nanocrystalline copper thin films. The use of nanosized (<5 nm) beam TEM for collecting spot diffraction patterns renders an order magnitude improvement spatial resolution compared backscatter scanning microscope. Electron precession is used reduce dynamical effects and increase reliability solutions. misorientation...
In this work, a recently developed electron diffraction technique called scanning transmission microscopy (D-STEM) is coupled with precession to obtain quantitative local texture information in damascene copper interconnects (1.8 µm–70 nm width) spatial resolution of less than 5 nm. Misorientation and trace analysis performed investigate the grain boundary distribution these lines. The results reveal strong variations lines upon downscaling. Lines width 1.8 µm exhibit 〈111〉 normal comprise...
Understanding the chemical and charge transport properties of grain boundaries (GBs) with high point defect concentrations (beyond dilute solution limit) in polycrystalline materials is critical for developing ion-conducting solids electrochemical energy conversion storage. Elucidation optimization GBs are hindered by large variations atomic structure, composition, chemistry within nanometers or Ångstroms GB interface, which limits a fundamental understanding electrical across along GBs....
The limitation of spatial resolution in orientation imaging via electron backscattered diffraction analysis the scanning microscope (SEM) makes it difficult to investigate microstructure nanocrystalline materials. use recently developed transmission (TEM) based product, known as ASTAR, offers possibility reliable orientation/phase mapping with a below 3 nm. In nanoprobe beam is scanned over specimen, and spot patterns are collected. precessed reduce dynamical effects improve pattern quality....
Crystal orientation mapping in the transmission electron microscope was used to quantify twin boundary length fraction per unit area for five Ta38Si14N48/SiO2 encapsulated Cu films with thicknesses range of 26–111 nm. The found be higher a given twin-excluded grain size these compared previously investigated SiO2 and Ta/SiO2 films. quantification allowed contribution boundaries effect resistivity assessed. It is shown that increased Ta38Si14N48 not result surface scattering, but it increase...
The recently developed precession electron diffraction (PED) technique in scanning transmission microscopy has been used to elucidate the local strain distribution and crystalline misorientation a CMOS fabricated strained Ge microdisk structure grown on Si substrate. Tensile GeSn structures are considered be potential compatible optical sources, as both Sn alloying can lead direct band-structure lasing. ability take nanometer resolution, experimental measurements of cross-sectional...
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Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – 8, 2013.
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.
Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – 30,
Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.
The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal carbon K edge in a 2 monolayer graphene sheet are studied. In previous work, we demonstrated use to compensate for channeling-induced reduction EELS when zone axis. case graphene, no enhancement is found usual experimental conditions, as not thick enough present channeling effects. Interestingly, though it that makes possible increase collection angle, and, thus, overall signal, without loss...
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.
Precession Electron Diffraction Detection and Phase Mapping of Retained Austenite Carbides in a Heat Treated Low Alloy Carbon Steel Using JEOL ARM 200 TEM with an AppFive Topspin System for Synchronized Beam Scanning - Volume 20 Issue S3
Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.
Transformations in Li-rich layered oxides have been extensively studied recently for their potential application Li-ion batteries. These materials attracted a lot of interest due to the high capacity offered by them. However, structure these pristine state is not clearly understood. Several reports assigned be trigonal (R-3m), monoclinic (c2/m), or combination both (composite). The present study discusses Li 1.2 (Ni 0.13 Mn 0.54 Co ) O 2 prepared with two different morphologies: plates and...