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Photoelectric Emission Measurements for CVD Grown Polycrystalline Diamond Films

Description: We examined CVD grown polycrystalline diamond films having different methane concentrations to detect defects and study the possible correlation between the methane concentration used during the growth process and the defect density. SEM and Raman results show that the amorphous and sp2 carbon content of the films increases with methane concentration. Furthermore, photoelectric emission from diamond is confirmed to be a two-photon process, hence the electrons are emitted from normally unoccupie… more
Date: August 1999
Creator: Hassan, Tarek
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Actinic imaging of native and programmed defects on a full-field mask

Description: We describe the imaging and characterization of native defects on a full field extreme ultraviolet (EUV) mask, using several reticle and wafer inspection modes. Mask defect images recorded with the SEMA TECH Berkeley Actinic Inspection Tool (AIT), an EUV-wavelength (13.4 nm) actinic microscope, are compared with mask and printed-wafer images collected with scanning electron microscopy (SEM) and deep ultraviolet (DUV) inspection tools. We observed that defects that appear to be opaque in the SEM… more
Date: March 12, 2010
Creator: Mochi, I.; Goldberg, K. A.; Fontaine, B. La; Tchikoulaeva, A. & Holfeld, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Synthesis of High-Purity alpha-and beta-PbO and Possible Applications to Synthesis and Processing of Other Lead Oxide Materials

Description: The red, tetragonal form of lead oxide, alpha-PbO, litharge, and the yellow, orthorhombic form, beta-PbO, massicot, have been synthesized from lead(II) salts in aqueous media at elevated temperature. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the size, morphology, and crystallographic structural forms of the products. The role of impurities in the experimental synthesis of the materials and microstructural variations in the final products are descri… more
Date: November 12, 2009
Creator: Perry, Dale L. & Wilkinson, T. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Automated Steel Cleanliness Analysis Tool (ASCAT)

Description: The objective of this study was to develop the Automated Steel Cleanliness Analysis Tool (ASCATTM) to permit steelmakers to evaluate the quality of the steel through the analysis of individual inclusions. By characterizing individual inclusions, determinations can be made as to the cleanliness of the steel. Understanding the complicating effects of inclusions in the steelmaking process and on the resulting properties of steel allows the steel producer to increase throughput, better control the … more
Date: December 30, 2005
Creator: Group), Gary Casuccio (RJ Lee; Group), Michael Potter (RJ Lee; Group), Fred Schwerer (RJ Lee; University), Dr. Richard J. Fruehan (Carnegie Mellon & Steel), Dr. Scott Story (US
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Quantitative Assessment of Site Formation at the Dmanisi Archaeological Site, Republic of Georgia

Description: The focus of this thesis was to gather and analyze micromorphological and petrographic data on soils at the archaeological site of Dmanisi in order to better understand the extent to which the deposition and alteration of the sediments has affected the preservation of artifacts and faunal remains. A major goal of this research was to test hypothesis related to why bone material is discovered in some strata and not in others. This research focuses on the application of micromorphology (supplemen… more
Date: August 2013
Creator: Crislip, Peter S.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Analytical Electron Microscopy Characterization of Uranium-Contaminated Soils from the Fernald Site, FY1993 Report

Description: A combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and analytical electron microscopy (AEM) is being used to determine the nature of uranium in soils from the Fernald Environmental Management Project. The information gained from these studies is being used to develop and test remediation technologies. Investigations using SEM have shown that uranium is contained within particles that are typically 1 to 100 micrometers in diameter. … more
Date: October 1994
Creator: Buck, E. C.; Cunnane, J. C.; Brown, N. R. & Dietz, N. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Use of Reciprocal Lattice Layer Spacing in Electron Backscatter Diffraction Pattern Analysis

Description: In the scanning electron microscope (SEM), using electron backscattered diffraction (EBSD), it is possible to measure the spacing of the layers in the reciprocal lattice. These values are of great use in confirming the identification of phases. The technique derives the layer spacing from the HOLZ rings which appear in patterns from many materials. The method adapts results from convergent-beam electron diffraction (CBED) in the transmission electron microscope (TEM). For many materials the mea… more
Date: May 10, 1999
Creator: Michael, J. R. & Eades, J. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ultrafast scanning tunneling microscopy using a photoexcited low-temperature-grown gallium arsenide tips

Description: The invention of the scanning tunneling microscope (STM) revolutionized the field of surface science, enabling the first images of surface structure on an atomic length scale. In the quest for both atomic spatial and temporal resolution several groups have integrated an ultrafast optoelectronic switch which gates the current from the tip, achieving picosecond time resolution. In this paper, the authors describe a novel STM tip consisting of a cleaved GaAs substrate with a 1-{micro}m thick epila… more
Date: February 1, 1998
Creator: Donati, G. P.; Some, D.; Rodriguez, G. & Taylor, A. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Quantitative Sub-Angstrom Imaging Through ADF STEM

Description: ORNL/CP-100163 Annular dark-field (ADF) imaging in a scanning transmission electron microscope (STEM) at atomic resolution provides an incoherent image that can be described as the convolution between the intensity of the illuminating STEM probe and an object function consisting of localised sources at the atomic-column positions. It has been shown that the resolution limit of the microscope limits the accuracy to which the object function can be reconstructed [1]. Here we demonstrate how a num… more
Date: August 31, 1998
Creator: Nellist, P.D. & Pennycook, S.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Planar shock compression of spark plasma sintered B4C and B4C-TiB2 ceramic composites

Description: Article describes how blending of ceramic constituent phases enhances sinterability and performance in high strength ceramics. The authors describe how a near fully dense blended boron carbide (B4C)-titanium diboride (TiB2) composite produced through spark plasma sintering (SPS) is probed to understand the mechanical performance under dynamic uniaxial strain, or shock compression.
Date: January 24, 2024
Creator: Turnage, Scott A.; Clayton, John D.; Rodriguez, Jonathan; Scharf, Thomas W. & Williams, Cyril L.
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Cylindrical Wire Electrical Discharge Machining of Metal Bond Diamond Wheels- Part II: Wheel Wear Mechanism

Description: The use of stereo scanning Electron Microscopy (SEM) to investigate the wear mechanism of the wire EDM true metal bond diamond wheel for ceramic grinding is presented. On the grinding wheel, a wedge-shape removal part was machined to enable the examination and measurement of the worn wheel surfaces using the stereo SEM. The stereo SEM was calibrated by comparing results of depth profile of a wear groove with the profilometer measurements. On the surface of the grinding wheel after wire EDM trui… more
Date: January 22, 2002
Creator: McSpadden, SB
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Direct Observations of Defect Structures in Optoelectronic Materials by Z-Contrast STEM

Description: Optoelectronic semiconductor materials have wide and important technological applications. For example, wide gap nitride semiconductors have attracted significant attention recently due to their promising performance as short-wavelength light emitting diodes (LEDs) and blue lasers, while HgCdTe II-VI semiconductors are the most promising candidates for applications as infrared detectors, or large array x-ray or r-ray detectors. In this paper, two examples are given to show that high-resolution … more
Date: August 31, 1998
Creator: Beaumont, B.; Browning, N. D.; Chen, Y. P.; Faurie, J. P.; Gibart, P.; Nellist, P. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Structure of low-density nanoporous dielectrics revealed by low-vacuum electron microscopy and small-angle x-ray scattering

Description: We use low-vacuum scanning electron microscopy to image directly the ligament and pore size and shape distributions of representative aerogels over a wide range of length scales ({approx} 10{sup 0}-10{sup 5} nm). The images are used for unambiguous, real-space interpretation of small-angle scattering data for these complex nanoporous systems.
Date: June 5, 2006
Creator: Kucheyev, S O; Toth, M; Baumann, T F; Hamza, A V; Ilavsky, J; Knowles, W R et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Lithographic measurement of EUV flare in the 0.3-NA Micro ExposureTool optic at the Advanced Light Source

Description: The level of flare present in a 0.3-NA EUV optic (the MET optic) at the Advanced Light Source at Lawrence Berkeley National Laboratory is measured using a lithographic method. Photoresist behavior at high exposure doses makes analysis difficult. Flare measurement analysis under scanning electron microscopy (SEM) and optical microscopy is compared, and optical microscopy is found to be a more reliable technique. In addition, the measured results are compared with predictions based on surface rou… more
Date: January 1, 2005
Creator: Cain, Jason P.; Naulleau, Patrick & Spanos, Costas J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Use of strain-annealing to evolve the grain boundary character distribution in polycrystalline copper

Description: We have used a two-step (low and high temperature) strain-annealing process to evolve the grain boundary character distribution (GBCD) in fully recrystallized oxygen-free electronic (OFE) Cu bar that was forged and rolled. Orientation imaging microscopy has been used to characterize the GBCD after each step in the processing. The fraction of special grain boundaries was {similar_to}70% in the starting recrystallized material. Three different processing conditions were employed: high, moderate, … more
Date: November 6, 1996
Creator: King, W.E. & Schwartz, A.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Scanning tunneling microscopy of Si donors in GaAs

Description: Using scanning tunneling microscopy, we have identified and characterized Si donors (Si{sub Ga}) in GaAs located on the (110) surface and in subsurface layers. Si{sub Ga} on the surface shows localized features with characteristic structures in good agreement with a recent theoretical calculation. Si{sub Ga} in subsurface layers appears as delocalized protrusions superimposed on the background lattice, which are interpreted in terms of the modification of the tunneling due to the tip-induced ba… more
Date: July 1, 1993
Creator: Zheng, J.F.; Weber, E.R.; Liu, X.; Newman, N.; Ogletree, D.F. & Salmeron, M.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Environmental scanning electron microscope (ESEM). Final report

Description: The Environmental Scanning Electron Microscope (ESEM) was acquired by a grant from the Department of Energy University Research Instrumentation Program and matching funds from Lehigh University and industry. The equipment is installed as part of the electron microscopy laboratories and is being utilized on a regular basis. Over 20 graduate and undergraduate students from the Department of Materials Science and Engineering as well as other department in the University have included this instrume… more
Date: November 1, 1998
Creator: Marder, A.; Barmak, K. & Williams, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Stress corrosion cracking behavior of irradiated model austenitic stainless steel alloys.

Description: Slow-strain-rate tensile tests (SSRTs) and posttest fractographic analyses by scanning electron microscopy were conducted on 16 austenitic stainless steel (SS) alloys that were irradiated at 289 C in He. After irradiation to {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2} and {approx}0.9 x 10{sup 21} n{center_dot}cm{sup {minus}2} (E >1 MeV), significant heat-to-heat variations in the degree of intergranular and transgranular stress corrosion cracking (IGSCC and TGSCC) were observed. F… more
Date: July 16, 1999
Creator: Chung, H. M.; Karlsen, T. M.; Ruther, W. E.; Shack, W. J. & Strain, R. V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Investigation of structural morphology and electrical properties of graphene-C₆₀ hybrids

Description: This article reports on the electrophoretic deposition of C₆₀ on graphene. The results suggest that graphene based C₆₀ structures are attractive as flexible transparent electrodes and are excellent electron accepting/charge transport materials for the construction of efficient photovoltaic devices.
Date: May 2, 2017
Creator: Chugh, Srishti; Biswas, Chandan; Echegoyen, Luis & Kaul, Anupama
Item Type: Refine your search to only Article
Partner: UNT College of Engineering
open access

Femtosecond scanning tunneling microscope

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). By combining scanning tunneling microscopy with ultrafast optical techniques we have developed a novel tool to probe phenomena on atomic time and length scales. We have built and characterized an ultrafast scanning tunneling microscope in terms of temporal resolution, sensitivity and dynamic range. Using a novel photoconductive low-temperature-grown… more
Date: November 1, 1998
Creator: Taylor, A. J.; Donati, G. P.; Rodriguez, G.; Gosnell, T. R.; Trugman, S. A. & Some, D. I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Surface structure and analysis with scanning probe microscopy and electron tunneling spectroscopy. Final report

Description: This report summarizes the results accomplished during the funding period of this grant (June 1, 1995 to May 31, 1998). The projects are (1) room-temperature atomic force microscopy (AFM) studies of NbSe{sub 3} doped with various elements and (2) low-temperature scanning tunneling microscopy (STM) studies of NbSe{sub 3}. In addition, AFM was used to study the surface morphology and defects of GaAs films grown on Ge and Ge/Si substracts.
Date: May 1, 1998
Creator: Hsu, Julia
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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