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Extreme Precipitation Strengthening in Ion-Implanted Nickel

Description: Precipitation strengthening of nickel was investigated using ion-implantation alloying and nanoindentation testing for particle separations in the nanometer range and volume fractions extending above 10O/O. Ion implantation of either oxygen alone or oxygen plus aluminum at room temperature was shown to produce substantial strengthening in the ion-treated layer, with yield strengths near 5 GPa in both cases. After annealing to 550"C the oxygen-alone layer loses much of the benefit, with its yiel… more
Date: May 3, 1999
Creator: Follstaedt, D. M.; Knapp, J. A.; Myers, S. M. & Petersen, G. A.
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Partner: UNT Libraries Government Documents Department
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Evolution of Vacancy Supersaturations in MeV Si Implanted Silicon

Description: High-energy Si implantation into silicon creates a net defect distribution that is characterized by an excess of interstitials near the projected range and a simultaneous excess of vacancies closer to the surface. This defect distribution is due to the spatial separation between the distributions of interstitials and vacancies created by the forward momentum transferred from the implanted ion to the lattice atom. This dissertation investigates the evolution of the near-surface vacancy excess in… more
Date: May 1999
Creator: Venezia, Vincent C.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A New Approach for Transition Metal Free Magnetic Sic: Defect Induced Magnetism After Self-ion Implantation

Description: SiC has become an attractive wide bandgap semiconductor due to its unique physical and electronic properties and is widely used in high temperature, high frequency, high power and radiation resistant applications. SiC has been used as an alternative to Si in harsh environments such as in the oil industry, nuclear power systems, aeronautical, and space applications. SiC is also known for its polytypism and among them 3C-SiC, 4H-SiC and 6H-SiC are the most common polytypes used for research purpo… more
Date: May 2013
Creator: Kummari, Venkata Chandra Sekhar
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Ion Beam Materials Analysis and Modifications At keV to MeV Energies at the University of North Texas

Description: This paper provides an overview of the Ion Beam Modification and Analysis Laboratory facilities and some of the current research projects.
Date: February 25, 2014
Creator: Rout, Bibhudutta; Dhoubhadel, Mangal; Poudel, Prakash R.; Kummari, Venkata C.; Lakshantha, Wickramaarachchige J.; Manuel, J. E. et al.
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Partner: UNT College of Arts and Sciences
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Oxidation of silicon implanted with high-dose aluminum

Description: Si(100) wafers were implanted with Al at 500 C to high doses at multi-energies and were oxidized in 1 atm flowing oxygen at 1000-1200 C. Morphology, structure, and oxidation behavior of the implanted and oxidized Si were studied using optical microscopy, atomic force microscopy, and cross-sectional transmission electron microscopy in conjunction with selected area electron diffraction and energy dispersive x-ray analysis. Large Al precipitates were formed and embedded near the surface region of… more
Date: December 31, 1994
Creator: Yang, Zunde; Du, Honghua & Withrow, S. P.
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Partner: UNT Libraries Government Documents Department
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BERNAS ION SOURCE DISCHARGE SIMULATION

Description: The joint research and development program is continued to develop steady-state ion source of decaborane beam for ion implantation industry. Bemas ion source is the wide used ion source for ion implantation industry. The new simulation code was developed for the Bemas ion source discharge simulation. We present first results of the simulation for several materials interested in semiconductors. As well the comparison of results obtained with experimental data obtained at the ITEP ion source test… more
Date: August 26, 2007
Creator: Rudskoy, I.; Kulevoy, T. V.; Petrenko, S. V.; Kuibeda, R. P.; Seleznev, D. N.; Pershin, v. I. et al.
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Partner: UNT Libraries Government Documents Department
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Direct Comparison Between Modeling and Experiment: An (Alpha)-Fe Ion Implantation Study

Description: Advances in computational capability and modeling techniques, as well as improvements in experimental characterization methods offer the possibility of directly comparing modeling and experiment investigations of irradiation effects in metals. As part of a collaboration among the Instituto de Fusion Nuclear (DENIM), Lawrence Livermore National Laboratory (LLNL) and CIEMAT, single and polycrystalline {alpha}-Fe samples have been irradiated with 150 keV Fe-ions to doses up to several dpa. The irr… more
Date: January 25, 2001
Creator: Marian, J.; Wirth, B. D.; Perlado, J. M.; Diaz de la Rubia, T.; Schaublin, R.; Lodi, D. et al.
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Partner: UNT Libraries Government Documents Department
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Annealing studies of visible light emission from silicon nanocrystals produced by implantation

Description: The annealing behavior of silicon implanted SiO{sub 2} layers is studied using continuous and time-gated photoluminescence (PL). Two PL emission bands are observed. A band centered at 560 nm is present in as implanted samples and it is still observed after 1000 {degrees}C annealing. The emission time is fast (0.2 -2 ns). A second band centered at 780 nm further increases when hydrogen annealing was performed. The emission time is long (1 {mu}s - 0.3 ms).
Date: December 31, 1996
Creator: Ghislotti, G.; Nielsen, B. & Di Mauro, L.F.
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Partner: UNT Libraries Government Documents Department
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Stable, free-standing Ge nanocrystals

Description: Free-standing Ge nanocrystals that are stable under ambient conditions have been synthesized in a two-step process. First, nanocrystals with a mean diameter of 5 nm are grown in amorphous SiO{sub 2} by ion implantation followed by thermal annealing. The oxide matrix is then removed by selective etching in diluted HF to obtain free-standing nanocrystals on a Si wafer. After etching, nanocrystals are retained on the surface and the size distribution is not significantly altered. Free-standing nan… more
Date: January 28, 2005
Creator: Sharp, I. D.; Xu, Q.; Liao, C. Y.; Yi, D. O.; Beeman, J. W.; Liliental-Weber, Z. et al.
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Partner: UNT Libraries Government Documents Department
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Detection of low energy single ion impacts in micron scaletransistors at room temperature

Description: We report the detection of single ion impacts throughmonitoring of changes in the source-drain currents of field effecttransistors (FET) at room temperature. Implant apertures are formed inthe interlayer dielectrics and gate electrodes of planar, micro-scaleFETs by electron beam assisted etching. FET currents increase due to thegeneration of positively charged defects in gate oxides when ions(121Sb12+, 14+, Xe6+; 50 to 70 keV) impinge into channel regions. Implantdamage is repaired by rapid the… more
Date: October 15, 2007
Creator: Batra, A.; Weis, C. D.; Reijonen, J.; Persaud, A.; Schenkel, T.; Cabrini, S. et al.
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Partner: UNT Libraries Government Documents Department
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Multiband GaNAsP Quaternary Alloys

Description: We have synthesized GaN{sub x}As{sub 1-y}P{sub y} alloys (x {approx} 0.3-1% and y = 0-0.4) using nitrogen N ion implantation into GaAsP epilayers followed by pulsed laser melting and rapid thermal annealing techniques. As predicted by the band anticrossing model, the incorporation of N splits the conduction band (E{sub M}) of the GaAs{sub 1-y}P{sub y} substrate, and strong optical transitions from the valence band to the lower (E{sub -}) and upper (E{sub +}) conduction subbands are observed. Th… more
Date: December 8, 2005
Creator: Yu, K. M.; Walukiewicz, W.; Ager, J. W., III; Bour, D.; Farshchi, R.; Dubon, O. D. et al.
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Partner: UNT Libraries Government Documents Department
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STATUS OF ITEP DECABORANE ION SOURCE PROGRAM.

Description: The joint research and development program is continued to develop steady-state ion source of decaborane beam for ion implantation industry. Both Freeman and Bemas ion sources for decaborane ion beam generation were investigated. Decaborane negative ion beam as well as positive ion beam were generated and delivered to the output of mass separator. Experimental results obtained in ITEP are presented.
Date: August 26, 2007
Creator: Kulevoy, T. V.; Petrenko, S. V.; Kuibeda, R. P.; Seleznev, D. N.; Kozlov, A. V.; Stasevich, Yu. B. et al.
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Partner: UNT Libraries Government Documents Department
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The role of AlN encapsulation of GaN during implant activation annealing

Description: With the demonstration of implant doping of GaN and the resulting need to perform the activation anneal at 1100 C, details of thermal stability of the GaN surface needs to be understood. This work reports on the use of a sputtered AlN encapsulant to preserve the surface of GaN during such annealing. The surface was characterized by formation of Pt/Au Schottky contacts and by AES. Schottky contacts deposited an GaN annealed wtih the AlN encapsulant displayed good rectification properties while t… more
Date: September 1, 1996
Creator: Zolper, J. C.; Rieger, D. J.; Baca, A. G.; Pearton, S. J.; Lee, J.W.; Vartulli, C.R. et al.
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Partner: UNT Libraries Government Documents Department
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Scanning tunneling microscopy and atomic force microscopy of Au implanted in highly ordered pyrolytic graphite

Description: Surfaces of highly oriented pyrolytic graphite implanted with gold were studied by both constant current STM, constant force, and tapping mode AFM. Gold colloids were observed by both constant current STM and tapping mode AFM. The surfaces can be modified by applying currents of {plus_minus}4 V and 1 nA. In addition, pyramidal and faceted structures were observed on sample surfaces suggesting the presence of diamond microcrystals.
Date: January 1, 1996
Creator: Tung, Y.S.; Ueda, A.; Henderson, D.O.; Mu, R.; Gu, Z.; White, C.W. et al.
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Partner: UNT Libraries Government Documents Department
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Toward a predictive atomistic model of ion implantation and dopant diffusion in silicon

Description: We review the development and application of kinetic Monte Carlo simulations to investigate defect and dopant diffusion in ion implanted silicon. In these type of Monte Carlo models, defects and dopants are treated at the atomic scale, and move according to reaction rates given as input principles. These input parameters can be obtained from first principles calculations and/or empirical molecular dynamics simulations, or can be extracted from fits to experimental data. Time and length scales d… more
Date: September 18, 1998
Creator: Caturla, M.; Johnson, M. D. & Zhu, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Structural investigation of B{sup +} ion implantation induced amorphization in polycrystalline Ni thin films

Description: High fluence metalloid ion implantation have been shown to induce amorphous phase formation in transition metals systems. In this study, electron energy loss spectroscopy and energy filtered selective area electron diffraction have been used along with conventional TEM to characterize the structural and electronic changes resulting from B{sup +} ion implantation into polycrystalline Ni thin films.
Date: June 1, 1996
Creator: Liu, P.C.; Zaluzec, N.J.; Okamoto, P.R. & Meshii, M.
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Partner: UNT Libraries Government Documents Department
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Chip-Scale Nanofabrication of Single Spins and Spin Arrays in Diamond

Description: We demonstrate a technique to nanofabricate nitrogen vacancy (NV) centers in diamond based on broad-beam nitrogen implantation through apertures in electron beam lithography resist. This method enables high-throughput nanofabrication of single NV centers on sub-100-nm length scales. Secondary ion mass spectroscopy measurements facilitate depth profiling of the implanted nitrogen to provide three-dimensional characterization of the NV center spatial distribution. Measurements of NV center cohere… more
Date: July 2, 2010
Creator: Toyli, David M.; Weis, Christoph D.; Fuchs, D.; Schenkel, Thomas & Awschalom, David D.
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Partner: UNT Libraries Government Documents Department
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Non-magnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting

Description: The electronic and magnetic effects of intentional compensation with non-magnetic donors are investigated in the ferromagnetic semiconductors Ga1-xMnxAs and Ga1-xMnxP synthesized using ion implantation and pulsed-laser melting (II-PLM). It is demonstrated that compensation with non-magnetic donors and MnI have similarqualitative effects on materials properties. With compensation TC decreases, resistivity increases, and stronger magnetoresistance and anomalous Hall effect attributed to skew scat… more
Date: February 5, 2008
Creator: Scarpulla, M. A.; Stone, P. R.; Sharp, I. D.; Haller, E. E.; Dubon, O. D.; Beeman, J. W. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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