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in subjects: "Recombination"

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Field Dependent Dopant Deactivation in Bipolar Devices at Elevated irradiation Temperatures

Metal-oxide-silicon capacitors fabricated in a bi-polar process were examined for densities of oxide trapped charge, interface traps and deactivated substrate acceptors following high-dose-rate irradiation at 100 C. Acceptor neutralization near the Si surface occurs most efficiently for small irradiation biases in depletion. The bias dependence is consistent with compensation and passivation mechanisms involving the drift of H{sup +} ions in the oxide and Si layers and the availability of holes… more

Date: August 15, 2000

Creator: WITCZAK,STEVEN C.; LACOE,RONALD C.; SHANEYFELT,MARTY R.; MAYER,DONALD C.; SCHWANK,JAMES R. & WINOKUR,PETER S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Back Contact Effects on the Electro-Optical Properties of CdTe/CdS Solar Cells

Studies of junction photoluminescence (PL) in CdTe/CdS solar cells reveal that back-contact application produces a dramatic qualitative change in the junction picosecond-PL spectrum. Prior to contact application, the spectrum has two peaks at energies of 1.501 eV and 1.457 eV, corresponding to recombination in regions of CdTeS alloy with 2% and 12% sulfur content, respectively. After contact application, the spectrum consists of a single broad peak at 1.48 eV. Previous studies have shown that t… more

Date: October 15, 1998

Creator: Levi, D. H.; Albin, D. S.; Gessert, T. A. (National Renewable Energy Laboratory) & Woods, L. M. (Department of Electrical Engineering, Colorado State University, Ft. Collins, CO)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Large-Signal Injection-Level Spectroscopy of Impurities in Silicon

Deep level defects in silicon are identified by measuring the recombination lifetime as a function of the injection level. The basic models for recombination at deep and shallow centers is developed. The defect used for the theoretical model is the well-known interstitial Fe ion in silicon. Data are presented on silicon samples ranging in defect content from intentionally Fe-doped samples to an ultra-pure float-zone grown sample. These data are analyzed in terms of the injection-level spectrosc… more

Date: October 16, 1998

Creator: Ahrenkiel, R. K. & Johnston, S. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement

Homologous recombination (HR) repairs chromosome damage and is indispensable for tumor suppression in humans. RAD51 mediates the DNA strand pairing step in HR. RAD51AP1 (RAD51 Associated Protein 1) is a RAD51-interacting protein whose function has remained elusive. Knockdown of RAD51AP1 in human cells by RNA interference engenders sensitivity to different types of genotoxic stress. Moreover, RAD51AP1-depleted cells are impaired for the recombinational repair of a DNA double-strand break and exh… more

Date: April 11, 2007

Creator: Wiese, Claudia; Dray, Eloise; Groesser, Torsten; San Filippo,Joseph; Shi, Idina; Collins, David W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Surface photovoltage measurements and finite element modeling of SAW devices.

Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined succe… more

Date: March 1, 2012

Creator: Donnelly, Christine

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Recombination Parameters for Antimonide-Based Semiconductors using RF Photoreflection Techniques

RF photoreflection measurements and PC-1D simulations have been used to evaluate bulk and surface recombination parameters in antimonide-based materials. PC-1D is used to simulate the photoconductivity response of antimonide-based substrates and doubly-capped epitaxial layers and also to determine how to extract the recombination parameters using experimental results. Excellent agreement has been obtained with a first-order model and test structure simulation when Shockley-Reed-Hall (SRH) recom… more

Date: October 10, 2002

Creator: Kumar, R. J.; Borrego, J. M.; Dutta, P. S.; Gutmann, R. J.; Wang, C. A.; Martinelli, R. U. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Building Biochips: A Protein Production Pipeline

Protein arrays are emerging as a practical format in which to study proteins in high-throughput using many of the same techniques as that of the DNA microarray. The key advantage to array-based methods for protein study is the potential for parallel analysis of thousands of samples in an automated, high-throughput fashion. Building protein arrays capable of this analysis capacity requires a robust expression and purification system capable of generating hundreds to thousands of purified recombi… more

Date: February 9, 2004

Creator: de Carvalho-Kavanagh, M & Albala, J S

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Photopumped x-ray laser research on Saturn

Using Saturn as a driver, we are pursuing both photoresonantly pumped and photoionization/recombination lasers. Our lasing targets are gas cells with thin windows that are pumped by a z pinch 2 cm away radiating 10 TW. In both schemes the lasant and gas fill is neon. We will present evidence for inversion in the sodium/neon photoresonant scheme but we have yet to detect the lasing transition itself. To increase our chances of measuring this line we have introduced potassium into a sodium z-pinc… more

Date: August 1, 1993

Creator: Nash, T. J.; Spielman, R. B.; Vargas, M. & Ruggles, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Selectively excited blue luminescence in heavily Mg doped p-type GaN

The emission at {approx}2.8 eV from heavily doped p-GaN, known as the blue luminescence (BL), has been studied by selective excitation using a dye laser tunable between 2.7-3.0 eV. The peak position and intensity of the BL are found to exhibit an unusual dependence on the excitation photon energy. We have explained our results with a shallow-donor and deep-acceptors pair recombination model which includes potential fluctuations induced by heavy doping. We found a ''critical energy'' of {approx}… more

Date: December 31, 2000

Creator: Colton, John S. & Yu, Peter Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Screening Resonances In Plasmas

When it was suggested that a new recombination mechanism (Resonant Radiative Recombination (RRR)) which, based on very general physical arguments, should happen in dense plasmas and promises to provide useful information for the local temperature and density diagnostics of plasmas, they assumed the existence of screening resonances. For model potentials the existence of screening resonances has been demonstrated beyond reasonable doubt in a number of calculations. The key question, how well tho… more

Date: December 1, 1998

Creator: Winkler, P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Recombination Lifetimes Using the RCPCD Technique: Comparison with Other Methods

The theory and operation of the resonance-coupled photoconductive decay (RCPCD) technique is described. Examples are presented of data measured on a wide variety of sample types. The RCPCD technique has been applied to a variety of wafer and thin-film materials. Using this technique, we can measure recombination lifetime over at least three decades of injection level. We can also measure relative values of minority-carrier mobility and diffusion length. By scanning the excitation wavelength, we… more

Date: January 1, 2005

Creator: Ahrenkiel, R. K.; Johnston, S. W. & Dashdorj, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Investigation of Electrical Activity of Dislocation and Grain Boundary in Polycrystalline Float Zone Silicon

In this paper, the charge carrier recombination behavior of grain boundaries(GBs) and intra-grain dislocations in high purity polycrystalline float-zone(FZ) silicon were studied by electron beam induced current (EBIC), laser microwave photoconductance decay (PCD) and preferential etching/Normaski optical microscopy. It was found that the lifetime on a single wafer increased from~10?s to 100?s as the average grain size varied from 100?m to several millimeters, while both dislocations near the su… more

Date: May 1, 2003

Creator: Lu, J.; Rozgonyi, G.; Kordas, L. & Ciszek, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Activated recombinative desorption: a potential component in mechanisms of spacecraft glow

The concept of activated recombination of atomic species on surfaces is capable of explaining the production of vibrationally and translationally excited desorbed molecular species. Equilibrium statistical mechanics predicts that the molecular quantum state distributions of desorbing molecules is a function of only the surface temperature when the adsorption probability is unity and independent of initial collision conditions. In most cases though the adsorption probability is dependent upon in… more

Date: January 1, 1985

Creator: Cross, J.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Unraveling the Fanconi anaemia-DNA repair connection through DNA helicase and translocase activities

How the Fanconi anaemia (FA) chromosome stability pathway functions to cope with interstrand crosslinks and other DNA lesions has been elusive, even after FANCD1 proved to be BRCA2, a partner of Rad51 in homologous recombination. The identification and characterization of two new Fanconi proteins having helicase motifs, FANCM and FANCJ/BRIP1/BACH1, implicates the FANC nuclear core complex as a participant in recognizing or processing damaged DNA, and the BRIP1 helicase as acting independently o… more

Date: August 16, 2005

Creator: Thompson, L H

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dissociative recombination of H{sub 3}{sup +}

Recent experiments by Larsson et al. have confirmed the prediction of a high energy ({approximately} 9.5 eV) peak in cross section for dissociative recombination of H{sub 3}{sup +}. This peak is caused by four doubly excited resonance states of H{sub 3}. Electron scattering. Calculations using the complex Kohn method provide resonance positions and widths as functions of the internuclear geometry. This information was used as input to a wave packet calculation for the dissociation dynamics on a… more

Date: December 1, 1993

Creator: Orel, A. E.; Kulander, K. C. & Lengsfield, B. H. III

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A Microsphere-Based Short-Wavelength Recombination X-Ray Laser

We describe a scheme for obtaining very short wavelengths ({lambda} {similar_to} 10{Angstrom}) in recombination lasers. The rapid cooling rates necessary to achieve population inversion during recombination are attained by adiabatic expansion of sub micron spheres. The lasing region is made up of many such spheres. The spheres are heated impulsively by a powerful picosecond laser. First, they ionize, then as they expand, they cool and recombine. We have calculated the optimum sphere size and in… more

Date: April 1992

Creator: Valeo, E. J. & Cowley, S. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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'Giant' multishell CdSe nanocrystal quantum dots with supporessed blinking: novel fluorescent probes for real-time detection of single-molecule events

We reported for the first time that key nanocrystal quantum dot (NQD) optical properties-quantum yield, photobleaching and blinking-can be rendered independent ofNQD surface chemistry and environment by growth of a very thick, defect-free inorganic shell. Here, we show the precise shell-thickness dependence of these effects. We demonstrate that 'giant-shell' NQDs can be largely non-blinking for observation times as long as 54 minutes and lhat on-time fractions are independent of experimental ti… more

Date: January 1, 2009

Creator: Hollingsworth, Jennifer A; Vela, Javier; Htoon, Han; Klimov, Victor I; Casson, Amy R & Chen, Yongfen

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Filling-factor dependence of magneto-luminescence in IT-VT QWs with 2DEG

Photoluminescence spectra of modulation-doped quantum well structures based on IT--VT semiconductors (CdTe/CdMgTe and ZnSe/ZnBeMgSe) were studied in high magnetic fields it the range of 2D electron concentrations of (1 --5) x 1011 cm2. The following peculiarities were found at low magnetic fields: (i) linear increase of the photoluminescence energy with increasing magnetic fields, (ii) jumps in this dependence at integer filling-factors, (iii) periodical changing of Zeeman splitting. The observ… more

Date: January 1, 2003

Creator: Gurevich, A. S.; Astakhov, G. V.; Suris, R. A. (Robert A.); Kochereshko, V. P.; Yakovlev, D. R.; Ossau, W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Analysis of Recombination Processes in 0.5-0.6 eV Epitaxial GaInAsSb Lattice-matched to GaSb

This work summarizes recent data on minority carrier lifetime in n- and p-type double heterostructures (DHs) of 0.5-0.6 eV GaInAsSb confined with GaSb and AlGaAsSb cap layers. Recombination times were measured by time-resolved photoluminescence (TRPL) and by optical frequency response (OFR) to sinusoidal excitation. It was shown that one of the mechanisms responsible for interface recombination in GaSb/GaInAsSb/GaSb DHs is thermionic emission of carriers over the heterobarrier. Considerable imp… more

Date: June 9, 2004

Creator: Donetsky, D.; Anikeev, S.; Gu, N.; Belenky, G.; Luryi, S.; Wang, C. A. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Leading Particle Effect from Heavy-Quark Recombination

The leading particle effect in charm hadroproduction is an enhancement of the cross section for a charmed hadron D in the forward direction of the beam when the beam hadron has a valence parton in common with the D. The large D+/D- asymmetry observed by the E791 experiment is an example of this phenomenon. We show that the heavy-quark recombination mechanism provides an economical explanation for this effect. In particular, the D+/D- asymmetry can be fit reasonably well using a single parameter… more

Date: May 1, 2002

Creator: Braten, Eric; Jia, Yu & Mehen, Thomas

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Some Aspects of the Mechanism of Bacteriophage Function. Progress Report, February 21, 1974--February 10, 1975

No Description Available.

Date: January 1, 1975

Creator: Freifelder, D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Hydrodynamic Instability of Ionization Fronts in HII Regions

The authors investigate hydrodynamic instability of accelerating ionization fronts with two dimensional hydrodynamic simulations. When recombination in the ionized region is turned off, Rayleigh-Taylor instability is effective. Perturbation grows up with classical Rayleigh-Taylor growth rate. In the case with recombination, the local difference of absorption profile works to smooth the surface. The perturbation does not grow and the amplitude follows a damped oscillations with time.

Date: August 21, 2003

Creator: Mizuta, A.; Kane, J.; Ryutov, D.; Remington, B.; Takabe, H. & Pound, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Supervised and unsupervised discretization methods for evolutionary algorithms

This paper introduces simple model-building evolutionary algorithms (EAs) that operate on continuous domains. The algorithms are based on supervised and unsupervised discretization methods that have been used as preprocessing steps in machine learning. The basic idea is to discretize the continuous variables and use the discretization as a simple model of the solutions under consideration. The model is then used to generate new solutions directly, instead of using the usual operators based on s… more

Date: January 24, 2001

Creator: Cantú-Paz, Erick

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Chloring e6 Sensitized Photovoltaic Cells: Effect of Co-Adsorbents on Cell Performance, Charge Transfer Resistance, and Charge Recombination Dynamics

This article investigates the effect of dye-aggregation-preventing co-adsorbents, cholic acid and deoxycholic acid, on the performance of dye-sensitized solar cells constructed using a metal-free sensitizer, chlorin e6 adsorbed onto TiO₂ surface.

Date: unknown

Creator: Lightbourne, Sherard K.S.; Gobeze, Habtom B.; Subbaiyan, Navaneetha K. & D'Souza, Francis

Item Type: Article

Partner: UNT College of Arts and Sciences