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Charge Collection Studies on Integrated Circuit Test Structures using Heavy-Ion Microbeams and MEDICI Simulation Calculations

Description: Ion induced charge collection dynamics within Integrated Circuits (ICs) is important due to the presence of ionizing radiation in the IC environment. As the charge signals defining data states are reduced by voltage and area scaling, the semiconductor device will naturally have a higher susceptibility to ionizing radiation induced effects. The ionizing radiation can lead to the undesired generation and migration of charge within an IC. This can alter, for example, the memory state of a bit, and… more
Date: May 2000
Creator: Guo, Baonian
Partner: UNT Libraries
open access

Energy Distribution of Sputtered Neutral Atoms from a Multilayer Target

Description: Energy distribution measurements of sputtered neutral particles contribute to the general knowledge of sputtering, a common technique for surface analysis. In this work emphasis was placed on the measurement of energy distribution of sputtered neutral atoms from different depths. The liquid Ga-In eutectic alloy as a sample target for this study was ideal due to an extreme concentration ratio gradient between the top two monolayers. In pursuing this study, the method of sputter-initiated resonan… more
Date: August 2000
Creator: Bigelow, Alan W.
Partner: UNT Libraries

The Stopping of Energetic Si, P and S Ions in Ni, Cu, Ge and GaAs Targets

Description: Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the … more
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: December 2001
Creator: Nigam, Mohit
Partner: UNT Libraries

Monte Carlo simulation and experimental studies of the production of neutron-rich medical isotopes using a particle accelerator.

Description: The developments of nuclear medicine lead to an increasing demand for the production of radioisotopes with suitable nuclear and chemical properties. Furthermore, from the literature it is evident that the production of radioisotopes using charged-particle accelerators instead of nuclear reactors is gaining increasing popularity. The main advantages of producing medical isotopes with accelerators are carrier free radionuclides of short lived isotopes, improved handling, reduction of the radioact… more
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: May 2002
Creator: Rosencranz, Daniela Necsoiu
Partner: UNT Libraries
open access

A Novel Process for GeSi Thin Film Synthesis

Description: A unique process of fabricating a strained layer GexSi1-x on insulator is demonstrated. Such strained heterostructures are useful in the fabrication of high-mobility transistors. This technique incorporates well-established silicon processing technology e.g., ion implantation and thermal oxidation. A dilute GeSi layer is initially formed by implanting Ge+ into a silicon-on-insulator (SOI) substrate. Thermal oxidation segregates the Ge at the growing oxide interface to form a distinct GexSi1-x … more
Date: December 2007
Creator: Hossain, Khalid
Partner: UNT Libraries
open access

Investigation of Selected Optically-Active Nanosystems Fashioned using Ion Implantation

Description: Opto-electronic semiconductor technology continues to grow at an accelerated pace, as the industry seeks to perfect devices such as light emitting diodes for purposes of optical processing and communication. A strive for greater efficiency with shrinking device dimensions, continually pushes the technology from both a design and materials aspect. Nanosystems such a quantum dots, also face new material engineering challenges as they enter the realm of quantum mechanics, with each system and ma… more
Date: May 2006
Creator: Mitchell, Lee
Partner: UNT Libraries
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Ion-Induced Damage In Si: A Fundamental Study of Basic Mechanisms over a Wide Range of Implantation Conditions

Description: A new understanding of the damage formation mechanisms in Si is developed and investigated over an extended range of ion energy, dose, and irradiation temperature. A simple model for dealing with ion-induced damage is proposed, which is shown to be applicable over the range of implantation conditions. In particular the concept of defect "excesses" will be discussed. An excess exists in the lattice when there is a local surplus of one particular type of defect, such as an interstitial, over i… more
Date: May 2006
Creator: Roth, Elaine Grannan
Partner: UNT Libraries
open access

Magnetotransport Properties of AlxIn1-xAsySb1-y/GaSb and Optical Properties of GaAs1-xSbx

Description: Multilayer structures of AlxIn1-xAsySb1-y/GaSb (0.37 £ x £ 0.43, 0.50 £ y £ 0.52), grown by molecular beam epitaxy on GaSb (100) substrates were characterized using variable temperature Hall and Shubnikov-de Haas techniques. For nominally undoped structures both p and n-type conductivity was observed. The mobilities obtained were lower than those predicted by an interpolation method using the binary alloys; therefore, a detailed analysis of mobility versus temperature data was performed to … more
Date: May 2003
Creator: Lukic- Zrnic, Reiko
Partner: UNT Libraries
open access

Neutron Transmutation and Hydrogenation Study of Hg₁₋xCdxTe

Description: Anomalous Hall behavior of HgCdTe refers to a "double cross-over" feature of the Hall coefficient in p-type material, or a peak in the Hall mobility or Hall coefficient in n-type material. A magnetoconductivity tensor approach was utilized to identify presence of two electrons contributing to the conduction as well as transport properties of each electron in the material. The two electron model for the mobility shows that the anomalous Hall behavior results from the competition of two electron… more
Date: December 2007
Creator: Zhao, Wei
Partner: UNT Libraries
open access

Thorium and Uranium M-shell X-ray Production Cross Sections for 0.4 – 4.0 MeV Protons, 0.4 - 6.0 MeV Helium Ions, 4.5 – 11.3 MeV Carbon Ions, and 4.5 – 13.5 MeV Oxygen Ions.

Description: The M-shell x-ray production cross section for thorium and uranium have been determined for protons of energy 0.4 - 4.0 MeV, helium ions of energy 0.4 - 6.0 MeV, carbon ions of energy 4.5 - 11.3 MeV and oxygen ions of energy 4.5 - 13.5 MeV. The total cross sections and the cross sections for individual x-ray peaks in the spectrum, consisting of the following transitions Mz (M4-N2, M5-N3, M4-N3), Ma (M5-N6,7), Mb (M4-N6, M5-O3, M4- O2), and Mg (M4-O3, M5-P3, M3-N4, M3-N5), were compared to the t… more
Date: May 2011
Creator: Phinney, Lucas C.
Partner: UNT Libraries
open access

Ion Beam Synthesis of Carbon Assisted Nanosystems in Silicon Based Substrates

Description: The systematic study of the formation of β-SiC formed by low energy carbon ion (C-)implantation into Si followed by high temperature annealing is presented. The research is performed to explore the optimal annealing conditions. The formation of crystalline β-SiC is clearly observed in the sample annealed at 1100 °C for a period of 1 hr. Quantitative analysis is performed in the formation of β-SiC by the process of implantation of different carbon ion fluences of 1×1017, 2×1017, 5… more
Date: May 2011
Creator: Poudel, Prakash Raj
Partner: UNT Libraries

A Study of the Accuracy and Precision Among XRF, ICP-MS, and PIXE on Trace Element Analyses of Small Water Samples

Description: Poster for the 2011 University Scholars Day at the University of North Texas discussing a study of the accuracy and precision among XRF, ICP-MS, and PIXE on trace element analyses of small water samples.
Date: April 14, 2011
Creator: Patnaik, Ritish; Naik, Sahil N.; Hart, Aaron S.; Kummari, Venkata C.; Phinney, Lucas; Dhoubhadel, Mangal et al.
Partner: UNT Honors College
open access

The Angular Distribution and Total Flux of Neutrons Obtained from the Deuterium-Tritium Reaction

Description: Mono-energetic neutrons have been produced with the low-voltage Cockroft-Walton accelerator at North Texas State College using two different reactions. It is the purpose of this paper to report the angular distribution and total flux of the neutrons obtained from the T(D,n) reaction.
Date: 1956
Creator: Duggan, Jerome L.
Partner: UNT Libraries
open access

K-shell x-ray-production cross sections in 6C, 8O, 9F, 11Na, 12Mg, and 13Al, by 0.75- to 4.5-MeV protons

Description: Article discussing K-shell x-ray-production cross sections in 6C, 8O, 9F, 11Na, 12Mg, and 13AI, by 0.75- to 4.5-MeV protons.
Date: November 1, 1991
Creator: Yu, Y. C.; McNeir, M. R.; Weathers, Duncan L.; Duggan, Jerome L.; McDaniel, Floyd Del. (Floyd Delbert), 1942- & Lapicki, Gregory
Partner: UNT College of Arts and Sciences
open access

L- and M-shell x-ray production cross sections of Nd, Gd, Ho, Yb, Au, and Pb by 25-MeV carbon and 32-MeV oxygen ions

Description: Article discussing research on L- and M-shell x-ray production cross sections of Nd, Gd, Ho, Yb, Au, and Pb by 25-MeV carbon and 32-MeV oxygen ions.
Date: October 15, 1987
Creator: Andrews, M. C.; McDaniel, Floyd Del. (Floyd Delbert), 1942-; Duggan, Jerome L.; Miller, P. D.; Pepmiller, P. L.; Krause, H. F. et al.
Partner: UNT College of Arts and Sciences
open access

Projectile-charge-state dependence of target L-shell ionization by 1.86-MeV/amu fluorine and silicon ions and 1.8-MeV/amu chlorine ions

Description: This article discusses projectile-charge-state dependence of target L-shell ionization by 1.86-MeV/amu and silicon ions and 1.8-MeV/amu chlorine ions.
Date: April 1979
Creator: McDaniel, Floyd Del. (Floyd Delbert), 1942-; Toten, R. S.; Peterson, J. L.; Duggan, Jerome L.; Wilson, Scott R.; Gressett, J. D. et al.
Partner: UNT College of Arts and Sciences
open access

Projectile charge-state dependence of K-shell ionization by silicon ions: A comparison of Coulomb ionization theories for direct ionization and electron capture with x-ray production data

Description: Article discussing projectile charge-state dependence of K-shell ionization by silicon ions and a comparison of Coulomb ionization theories for direct ionization and electron capture with x-ray production data.
Date: October 1977
Creator: McDaniel, Floyd Del. (Floyd Delbert), 1942-; Duggan, Jerome L.; Basbas, George; Miller, P. D. & Lapicki, Gregory
Partner: UNT College of Arts and Sciences
open access

M-shell x-ray production cross sections in thin targets of ₇₉Au, ₈₂Pb, ₈₃Bi, and ₉₂U by 0.3 - 2.6-MeV ₁¹H+ and ₂⁴He+ ions

Description: Article discussing M-shell x-ray-production cross sections in thin targets of ₇₉Au, ₈₂Pb, ₈₃Bi, and ₉₂U by 0.3 - 2.6-MeV ₁⁴H+ and ₂⁴He+ ions.
Date: October 1982
Creator: Mehta, R.; Duggan, Jerome L.; Price, J. L.; McDaniel, Floyd Del. (Floyd Delbert), 1942- & Lapicki, Gregory
Partner: UNT College of Arts and Sciences
open access

₁¹H+ - and ₂⁴He+ - induced M-shell x-ray-production cross sections for selected elements in the rare-earth region

Description: Article on ₁¹H+ and ₂⁴He+ -induced M-shell x-ray-production cross sections for selected elements in the rare-earth region.
Date: December 1983
Creator: Mehta, R.; Duggan, Jerome L.; Price, J. L.; Kocur, P. M.; McDaniel, Floyd Del. (Floyd Delbert), 1942- & Lapicki, Gregory
Partner: UNT College of Arts and Sciences
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