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Investigation of elevated temperature aging effects on lithium-ion cells

Description: Electrical and chemical measurements have been made on 18650-size lithium-ion cells that have been exposed to calendar and cycle life aging at temperatures up to 70 C. Aging times ranged from 2 weeks at the highest temperature to several months under more moderate conditions. After aging, the impedance behavior of the cells was reversed from that found originally, with lower impedance at low state of charge and the total impedance was significantly increased. Investigations using a reference electrode showed that these changes are primarily due to the behavior of the cathode. Measurements of cell impedance as a function of cell voltage reveal a pronounced minimum in the total impedance at approximately 40--50% state-of-charge (SOC). Chemical analysis data are presented to support the SOC assignments for aged and unaged cells. Electrochemical impedance spectroscopy (EIS) data have been recorded at several intermediate states of charge to construct the impedance vs. open circuit voltage curve for the cell. This information has not previously been available for the LiNi{sub 0.85}Co{sub 0.15}O{sub 2} cathode material. Structural and chemical analysis information obtained from cell components removed during postmortems will also be discussed in order to reveal the true state of charge of the cathode and to develop a more complete lithium inventory for the cell.
Date: April 17, 2000
Creator: JUNGST,RUDOLPH G.; NAGASUBRAMANIAN,GANESAN & INGERSOLL,DAVID
Partner: UNT Libraries Government Documents Department

Impedance studies on Li-ion cathodes

Description: This paper describes the author's 2- and 3-electrode impedance results of metal oxide cathodes. These results were extracted from impedance data on 18650 Li-ion cells. The impedance results indicate that the ohmic resistance of the cell is very nearly constant with state-of-charge (SOC) and temperature. For example, the ohmic resistance of 18650 Li-ion cells is around 60 m{Omega} for different SOCS (4.1V to 3.0V) and temperatures from 35 C to {minus}20 C. However, the interfacial impedance shows a modest increase with SOC and a huge increase of between 10 and 100 times with decreasing temperature. For example, in the temperature regime (35 C down to {minus}20 C) the overall cell impedance has increased from nearly 200 m{Omega} to 8,000 m{Omega}. Most of the increase in cell impedance comes from the metal oxide cathode/electrolyte interface.
Date: April 17, 2000
Creator: NAGASUBRAMANIAN, GANESAN
Partner: UNT Libraries Government Documents Department

INTRA - BEAM SCATTERING MEASUREMENTS IN RHIC.

Description: RHIC in gold operation shows significant intra-beam scattering due to the high charge state of the stored ions. Intra-beam scattering leads to longitudinal and transverse emittance growth. The longitudinal emittance growth causes debunching in operation; the transverse emittance growth contributes to the reduction of the beam and luminosity lifetimes. The longitudinal and transverse beam growth was measured. Beam growth measurement are compared with computations.
Date: June 2, 2002
Creator: FISCHER,W.; CONNOLLY,R.; TEPIKIAN,S.; VAN ZEIJTS,J. & ZENO,K.
Partner: UNT Libraries Government Documents Department

Testing of a 50-kW wind-diesel hybrid system at the National Wind Technology Center

Description: To further the development of commercial hybrid power systems, the National Renewable Energy Laboratory (NREL), in collaboration with the New World Village Power Corporation (NWVP), tested a NWVP 50-kW wind-diesel hybrid system connected to a 15/50 Atlantic Orient Corporation (AOC) wind turbine. Testing was conducted from October 1995 through March 1996 at the National Wind Technology Center (NWTC). A main objective of the testing was to better understand the application of wind turbines to weak grids typical of small villages. Performance results contained in this paper include component characterization, such as power conversion losses for the rotary converter systems and battery round trip efficiencies. In addition, systems operation over this period is discussed with special attention given to dynamic issues. Finally, future plans for continued testing and research are discussed.
Date: July 1996
Creator: Corbus, D. A.; Green, J.; Allderdice, A.; Rand, K.; Bianchi, J. & Linton, E.
Partner: UNT Libraries Government Documents Department

Design diversity of HEVs with example vehicles from HEV competitions

Description: Hybrid Electric Vehicles (HEVS) can be designed and operated to satisfy many different operational missions. The three most common HEV types differ with respect to component sizing and operational capabilities. However, HEV technology offers design opportunities beyond these three types. This paper presents a detailed HEV categorization process that can be used to describe unique HEV prototype designs entered in college and university-level HEV design competitions. We explored possible energy management strategies associated with designs that control the utilization of the two on- board energy sources and use the competition vehicles to illustrate various configurations and designs that affect the vehicle`s capabilities. Experimental data is used to help describe the details of the power control strategies which determine how the engine and electric motor of HEV designs work together to provide motive power to the wheels.
Date: December 31, 1996
Creator: Duoba, M.; Larsen, R. & LeBlanc, N.
Partner: UNT Libraries Government Documents Department

Amp-hour counting control for PV hybrid power systems

Description: The performance of an amp-hour (Ah) counting battery charge control algorithm has been defined and tested using the Digital Solar Technologies MPR-9400 microprocessor based PV hybrid charge controller. This work included extensive field testing of the charge algorithm on flooded lead-antimony and valve regulated lead-acid (VRLA) batteries. The test results after one-year have demonstrated that PV charge utilization, battery charge control, and battery state of charge (SOC) has been significantly improved by providing maximum charge to the batteries while limiting battery overcharge to manufacturers specifications during variable solar resource and load periods.
Date: June 1, 1997
Creator: Hund, T.D. & Thompson, B.
Partner: UNT Libraries Government Documents Department

Further development of low noise MEVVA ion source

Description: Based on the idea of a space-charge-limited mode of operation, the influence of a pair of electrostatic meshes on the beam parameters of the LBNL MEVVA-5 ion source was investigated. The meshes were placed in the expansion zone of the vacuum arc plasma. Apart from reducing the level of beam current fluctuations, this mode of operation provides significant control over the ion charge state distribution of the extracted beam. These effects can be understood taking not only space charge but also the high-directed ion drift velocities into account that are the same for different ion charge states of a material. The results of simulations of the processes involved are in good agreement with the experimental results.
Date: August 28, 2001
Creator: Oks, Efim; Yushkov, George; Litovko, Irina; Anders, Andre & Brown, Ian
Partner: UNT Libraries Government Documents Department

ENERGY DISTRIBUTION OF TWO-ELECTRON IONIZATION OF HELIUM IN AN INTENSE LASER FIELD.

Description: It is well known that a neutral atom interacting with a strong laser field will ionize at sufficiently high intensity even for photon energies well below the ionization threshold. When the required number of photons becomes very large, this process is best described by the suppression of the Coulomb barrier by the laser's oscillating electric field, allowing the electron to tunnel into the continuum. As the laser intensity is increased, more tightly bound electrons may be successively liberated by this mechanism. Such a sequential multiple ionization, long accepted as a reasonable approach to the formidable problem of a multielectron atom interacting nonperturbatively with an intense electromagnetic field, provides fair estimates of the various charge state appearance intensities while the tunneling rates are in excellent agreement with single ionization yields. However, more accurate measurements revealed systematic and very large deviations from the tunneling rates: near appearance intensity under standard experimental conditions, the observed double ion yield is several orders of magnitude larger than predicted by the sequential rate. It soon became clear that electrons could not be considered as independent and that electron-electron correlation had to be taken into account. Dynamic correlations have been considered in several theories. First qualitatively in the shakeoff model; then empirically through the e-2e cross-section in the quantum/classical three-step model (tunnel ionization, acceleration by the oscillating electric field and e-2e recollision with the ion); recently through the so-called intense field many-body-S-matrix theory and a purely empirical model of collective tunnel ionization. The validity of these ideas has been examined using numerical models. The measurement of total ion yields over a dynamic range exceeding ten orders of magnitude, a major breakthrough made possible by the availability of high-repetition rate lasers at the beginning of the 90's, was for a long time the only quantitative data to confront ...
Date: September 24, 2000
Creator: LAFON,R.; CHALOUPKA,J.L.; SHEEHY,B.; DIMAURO,L.F.; PAUL,P.M.; AGOSTINI,P. et al.
Partner: UNT Libraries Government Documents Department

ENERGY DISTRIBUTION OF TWO-ELECTRON IONIZATION OF HELIUM IN AN INTENSE LASER FIELD.

Description: It is well known that a neutral atom interacting with a strong laser field will ionize at sufficiently high intensity even for photon energies well below the ionization threshold. When the required number of photons becomes very large, this process is best described by the suppression of the Coulomb barrier by the laser's oscillating electric field, allowing the electron to tunnel into the continuum. As the laser intensity is increased, more tightly bound electrons may be successively liberated by this mechanism. Such a sequential multiple ionization, long accepted as a reasonable approach to the formidable problem of a multielectron atom interacting nonperturbatively with an intense electromagnetic field, provides fair estimates of the various charge state appearance intensities while the tunneling rates are in excellent agreement with single ionization yields. However, more accurate measurements revealed systematic and very large deviations from the tunneling rates: near appearance intensity under standard experimental conditions, the observed double ion yield is several orders of magnitude larger than predicted by the sequential rate. It soon became clear that electrons could not be considered as independent and that electron-electron correlation had to be taken into account. Dynamic correlations have been considered in several theories. First qualitatively in the shakeoff model; then empirically through the e-2e cross-section in the quantum/classical three-step model (tunnel ionization, acceleration by the oscillating electric field and e-2e recollision with the ion); recently through the so-called intense field many-body-S-matrix theory and a purely empirical model of collective tunnel ionization. The validity of these ideas has been examined using numerical models. The measurement of total ion yields over a dynamic range exceeding ten orders of magnitude, a major breakthrough made possible by the availability of high-repetition rate lasers at the beginning of the 90's, was for a long time the only quantitative data to confront ...
Date: September 24, 2000
Creator: LAFON,R.; CHALOUPKA,J.L.; SHEEHY,B.; DIMAURO,L.F.; PAUL,P.M.; AGOSTINI,P. et al.
Partner: UNT Libraries Government Documents Department

MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.

Description: A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than l/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.
Date: June 28, 1999
Creator: REHAK,P.; SMITH,G.C.; WARREN,J.B. & YU,B.
Partner: UNT Libraries Government Documents Department

EXTRACTION OF HIGHLY CHARGED AU IONS FROM A MULTIAMPHERE ELECTRON BEAM EBIS AT BNL.

Description: Excellent progress has been made in the operation of the BNL Electron Beam Ion Source (EBIS), which is a prototype for an EBIS that could meet requirements for a RHIC preinjector. We have achieved very stable operation of the electron beam at 10 A through the EBIS trap. Ion injection of low charge gold ions from a LEVA [1] ion source and subsequent extraction of these ions with most probable charge state AU{sup 34+} has been demonstrated with electron beams up to 8A. The total ion charge for gold measured on current transformer at the EBIS exit was 55nC after a 30ms confinement period. This corresponds to {approx}85% of the theoretical ion trap capacity and exceeds our goal of 50% neutralization. The collected ion charge is proportional to the electron current and the gold charge state scales with the electron current density. Details of the EBIS configuration, total charge measurements, and TOF spectra are given.
Date: September 2, 2001
Creator: BEEBE,E.N.; ALESSI,J.G.; GOULD,O.; GRAHAM,D.; KPONOU,A.; PIKIN,A. et al.
Partner: UNT Libraries Government Documents Department

Examination of VRLA cells sampled from a battery energy storage system (BESS) after 30-months of operations

Description: Valve-Regulated Lead-Acid (VRLA) batteries continue to be employed in a wide variety of applications for telecommunications and Uninterruptible Power Supply (UPS). With the rapidly growing penetration of internet services, the requirements for standby power systems appear to be changing. For example, at last year's INTELEC, high voltage standby power systems up to 300-vdc were discussed as alternatives to the traditional 48-volt power plant. At the same time, battery reliability and the sensitivity of VRLAS to charging conditions (e.g., in-rush current, float voltage and temperature), continue to be argued extensively. Charge regimes which provide off-line charging or intermittent charge to the battery have been proposed. Some of these techniques go against the widely accepted rules of operation for batteries to achieve optimum lifetime. Experience in the telecom industry with high voltage systems and these charging scenarios is limited. However, GNB has several years of experience in the installation and operation of large VRLA battery systems that embody many of the power management philosophies being proposed. Early results show that positive grid corrosion is not accelerated and battery performance is maintained even when the battery is operated at a partial state-of-charge for long periods of time.
Date: June 8, 2000
Creator: Szymborski, Joseph; Hunt, George; Tsagalis, Angelo & Jungst, Rudolph G.
Partner: UNT Libraries Government Documents Department

X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources

Description: Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.
Date: May 1, 1999
Creator: Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang et al.
Partner: UNT Libraries Government Documents Department

MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.

Description: A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than 1/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.
Date: June 28, 1999
Creator: REHAK,P.; SMITH,G.C.; WARREN,J.B. & YU,B.
Partner: UNT Libraries Government Documents Department

Non-additive sputtering of niobium and tantalum as large neutral and ion clusters.

Description: An analysis of available literature data on both the positive ion emission from Nb and Ta bombarded by 6 keV/atom Au{sub m}{sup -} atomic and molecular ions (m=1, 2, 3) and positive ionization probabilities of Nb{sub n} and Ta{sub n} neutral clusters sputtered from the same metals by 5 keV Ar{sup +} ions have been conducted. Dependencies of cluster yields Y{sub n,m} (regardless of a charge state) on number of atoms n in a sputtered particle were found to follow a power law as Y{sub n,m} {approx} n{sup -{sigma}{sub m}} where {sigma}{sub m} decreased with an increase of m. A non-linear enhancement of yields for large Nb{sub n}{sup +} and Ta{sub n}{sup +} cluster ions (n>4) appeared to be due to a non-additive process of sputtering rather than because of a non-additive process of their ionization. A manifestation of the non-additive sputtering in kinetic energy distributions of secondary ions found to be different for atomic and cluster ions.
Date: September 23, 2002
Creator: Belykh, S. F.; Palitsin, V. V.; Veryovkin, I. V.; Adriaens, A. & Adams, F.
Partner: UNT Libraries Government Documents Department

Operational improvements of the Argonne ECR sources.

Description: The performance of the recently upgraded ATLAS 10.5 GHz ECR ion source (ECR 1) has continued to improve with a factor of 12 increase in the intensity of high charge state ions (O{sup 7+}, Ne{sup 9+}, Ni{sup 16+}, Kr{sup 17+}) and greater source stability. Use of the sputter technique with a natural nickel sample has produced a {sup 58}Ni{sup 17+} beam with an intensity of 16.0 e{mu}A. The solenoid power supplies are presently running at their maximum rated output and replacement of these supplies is planned to further increase the axial magnetic field. The MIVOC method has been employed at the 14 GHz ECR ion source (ECR 2) to produce a {sup 56}Fe{sup 15+} beam with a peak performance of 25.0 e{mu}A. Efficiency into the 15+ charge state has been measured at 0.47%. A high temperature oven was used to produce a {sup 50}Ti{sup 12+} beam with an intensity of 6.9 e{mu}A. A {sup 238}U{sup 37+} beam with an intensity of 3.0 e{mu}A was produced using the sputter technique. Use of a second frequency has been restored with a 50-100% increase over single frequency operation in the intensities of the medium charge states and a factor of 2 to 5 increase in the higher charge states.
Date: August 1, 2002
Creator: Vondrasek, R. C.; Scott, R. H.; Pardo, R. C. & Koivisto, H.
Partner: UNT Libraries Government Documents Department

A high transmission analyzing magnet for intense high charge state beams

Description: The low energy beam transport (LEBT) for VENUS will provide for extraction, mass analysis and transport to the axial injection line for the 88-Inch Cyclotron. The new LEBT was designed from the beginning to handle high intensity beams where space charge forces strongly affect the transmission. The magnet has a unique design with specially shaped poles to apply sextupole correction in both the horizontal and vertical plane.
Date: June 11, 2002
Creator: Leitner, M.; Abbott, S.R.; Leitner, D. & Lyneis, C.
Partner: UNT Libraries Government Documents Department

UNDERLINE PHYSICS OF E - MEVVA OPERATION.

Description: Recently substantial enhancement of high ion charge states was clearly observed in both the HCEI and ITEP E-MEVVA ion sources. These experimental set-ups have two different methods of measuring the ion charge state distributions. The results can be considered as a proof of the E-MEVVA principle. These results sparked discussions regarding, which physics effects are dominant. Basic physics seems straightforward, an ion charge state in E-MEVVA is determined by the number of collisions with fast electrons versus the number of encounters with neutrals and lower charge state ions during an ion dwell time in the drift channel. However, the fluxes of fast electrons, lower charge state ions, and neutrals encountered by an ion may be a consequence of numerous effects. Factors determining neutral fluxes might be poor vacuum conditions, desorption of adsorbed gas by the electron beam directly or indirectly due to stacking (E-beam reflection) and/or instabilities that cause heating and desorption. Flux and energy of the fast electrons is primarily determined by the electron gun output. But significant contributions from electron beam stacking, instabilities, as well as plasma electron heating, are possible.
Date: June 24, 2002
Creator: HERSHCOVITCH,A.; BATALIN,V.A.; BUGAEV,A.S; DEBOLT,N.; GUSHENETS,V.I. & AL, ET
Partner: UNT Libraries Government Documents Department

PROPOSAL FOR AN EBIS BASED RHIC PREINJECTOR.

Description: A proposed new heavy ion preinjector for RHIC is described. The progress made at BNL on the development of an Electron Beam Ion Source (EBIS) has increased our confidence that one can build a preinjector meeting RHIC requirements using an EBIS producing intermediate charge state heavy ions. A new RFQ and Linac will be required to accelerate beams from this source to an energy sufficient for injection into the AGS Booster. These are both straightforward devices, very similar to ones already in operation at other laboratories. Injection into the Booster will occur at the same location as the existing heavy ion injection from the Tandem Van de Graaff.
Date: November 6, 2000
Creator: ALESSI,J.G.; BEEBE,E.; KPONOU,A.; PIKIN,A.; PRELEC,K.; RAPARIA,D. et al.
Partner: UNT Libraries Government Documents Department

Design features of high-intensity medium-energy superconducting heavy-ion Linac.

Description: The proposed Rare Isotope Accelerator (RIA) requires the construction of a cw 1.4 GV superconducting (SC) linac that is capable of producing 400 kW beams of all ions from protons at 900 MeV to uranium at 400 MeV/u. The design of such a linac was outlined at the previous Linac conference. This linac will accelerate multiple-charge-states (multi-q) of the heaviest ion beams, for which the beam current is limited by ion-source performance. The linac consists of two different types of accelerating and focusing lattice: for uranium below {approx}85 MeV/u the focusing is provided by SC solenoids installed in cryostats with the SC resonators while in the high-beta section the focusing elements are located outside of the cryostats. A detailed design has been developed for the focusing-accelerating lattice of the linac. Beam dynamics studies have been performed with the goal of optimization of the linac structure in order to reduce a possible effective emittance growth of the multi-q uranium beam. A wide tuning range of the accelerating and focusing fields is required for acceleration of the variety of ions with different charge-to-mass ratios to the highest possible energy in single charge state mode. The focusing must be retuned for different ion masses to avoid resonance coupling between the transverse and longitudinal motions. Any visible impact of this coupling on the formation of beam halo must be avoided due to the high beam power.
Date: September 20, 2002
Creator: Ostroumov, P. N.
Partner: UNT Libraries Government Documents Department

Battery testing for photovoltaic applications

Description: Battery testing for photovoltaic (PV) applications is funded at Sandia under the Department of Energy`s (DOE) Photovoltaic Balance of Systems (BOS) Program. The goal of the PV BOS program is to improve PV system component design, operation, reliability, and to reduce overall life-cycle costs. The Sandia battery testing program consists of: (1) PV battery and charge controller market survey, (2) battery performance and life-cycle testing, (3) PV charge controller development, and (4) system field testing. Test results from this work have identified market size and trends, PV battery test procedures, application guidelines, and needed hardware improvements.
Date: November 1, 1996
Creator: Hund, T.
Partner: UNT Libraries Government Documents Department

Design and simulation of lithium rechargeable batteries

Description: Lithium -based rechargeable batteries that utilize insertion electrodes are being considered for electric-vehicle applications because of their high energy density and inherent reversibility. General mathematical models are developed that apply to a wide range of lithium-based systems, including the recently commercialized lithium-ion cell. The modeling approach is macroscopic, using porous electrode theory to treat the composite insertion electrodes and concentrated solution theory to describe the transport processes in the solution phase. The insertion process itself is treated with a charge-transfer process at the surface obeying Butler-Volmer kinetics, followed by diffusion of the lithium ion into the host structure. These models are used to explore the phenomena that occur inside of lithium cells under conditions of discharge, charge, and during periods of relaxation. Also, in order to understand the phenomena that limit the high-rate discharge of these systems, we focus on the modeling of a particular system with well-characterized material properties and system parameters. The system chosen is a lithium-ion cell produced by Bellcore in Red Bank, NJ, consisting of a lithium-carbon negative electrode, a plasticized polymer electrolyte, and a lithium-manganese-oxide spinel positive electrode. This battery is being marketed for consumer electronic applications. The system is characterized experimentally in terms of its transport and thermodynamic properties, followed by detailed comparisons of simulation results with experimental discharge curves. Next, the optimization of this system for particular applications is explored based on Ragone plots of the specific energy versus average specific power provided by various designs.
Date: August 1, 1995
Creator: Doyle, C.M.
Partner: UNT Libraries Government Documents Department

Wide-Bandgap Compound Semiconductors to Enable Novel Semiconductor Devices

Description: This report represents the completion of a three-year Laboratory-Directed Research and Development (LDRD) program that focused on research and development of GaN-based wide bandgap semiconductor materials (referred to as III-N materials). Our theoretical investigations include the determination of fundamental materials parameters from first-principles calculations, the study of gain properties of III-N heterostructures using a microscopic laser theory and density-functional-theory, charge-state calculations to determine the core structure and energy levels of dislocations in III-N materials. Our experimental investigations include time-resolved photoluminescence and magneto-luminescence studies of GaN epilayers and multiquantum well samples as well as x-ray diffraction studies of AlGaN ternary alloys. In addition, we performed a number of experiments to determine how various materials processing steps affect both the optical and electrical properties of GaN-based materials. These studies include photoluminescence studies of GaN epilayers after post-growth rapid thermal annealing, ion implantation to produce n- and p-type material and electrical and optical studies of plasma-etched structures.
Date: April 1, 1999
Creator: Crawford, M.H.; Chow, W.W.; Wright, A.F.; Lee, S.R.; Jones, E.D.; Han, J. et al.
Partner: UNT Libraries Government Documents Department