A5101494874- GaN-based semiconductor devices and materials
- Semiconductor Quantum Structures and Devices
- Medical Imaging Techniques and Applications
- Metal and Thin Film Mechanics
- Advanced X-ray and CT Imaging
- solar cell performance optimization
- Ga2O3 and related materials
- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Radiation Detection and Scintillator Technologies
- Semiconductor materials and devices
- Structural Analysis and Optimization
- Structural Health Monitoring Techniques
- Chalcogenide Semiconductor Thin Films
- Rocket and propulsion systems research
- Nuclear Physics and Applications
- Semiconductor materials and interfaces
- Vibration and Dynamic Analysis
- Plasma Diagnostics and Applications
- Advanced Materials Characterization Techniques
- Thermal Radiation and Cooling Technologies
- Particle Detector Development and Performance
- Structural Engineering and Vibration Analysis
- Inhalation and Respiratory Drug Delivery
- Silicon Carbide Semiconductor Technologies
Los Alamos National Laboratory
2011-2022
Arizona State University
2013-2018
General Electric (United States)
2003
University of Iowa
1986
University of Michigan
1977-1979
Roche (Switzerland)
1977
Central Electricity Generating Board
1962-1963
Abstract A collaborative study was conducted to evaluate the repeatability and reproducibility of FOSS FoodScan near-infrared spectrophotometer with artificial neural network calibration model database for determination fat, moisture, protein in meat products. Representative samples were homogenized by grinding according AOAC Official Method 983.18. Approximately 180 g ground sample placed a 140 mm round dish, dish FoodScan. The operator ID entered, product profile within software selected,...
In <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><inline-formula><tex-math notation="LaTeX">$_{x}$</tex-math></inline-formula></i> Ga <sub xmlns:xlink="http://www.w3.org/1999/xlink">1−</sub> N solar cells are ideal for use in extreme temperature applications due to their wide band gap and chemical stability. this paper, the details given growth, fabrication, characterization of xmlns:xlink="http://www.w3.org/1999/xlink"><inline-formula>...
We have investigated the ultrafast carrier dynamics in a 1 μm bulk In0.265Ga0.735N thin film grown using energetic neutral atom-beam lithography/epitaxy molecular beam epitaxy. Cathodoluminescence and X-ray diffraction experiments are used to observe existence of indium-rich domains sample. These give rise second population bi-exponential cooling is observed with characteristic lifetimes 1.6 14 ps at density 1.3 × 1016 cm−3. A combination band-filling, screening, hot-phonon effects gives...
A number of In-rich InGaN films with In contents in the 20–40% range have been grown at moderately low temperatures on sapphire and silicon substrates high growth rates using a versatile molecular beam epitaxy-type technology that utilizes an energetic N atoms called neutral atom lithography epitaxy to overcome reaction barriers group III-nitride system. Extensive characterization results crystalline, optical, electrical properties materials are reported. It was found N-rich conditions...
The III-N material class of semiconductors exhibits desirable properties for construction a cell integration with the thermal receiver concentrated solar plant. We design GaN-InGaN based operation at 450 °C. An MQW structure InGaN absorber is selected to improve voltage through improved quality. Cell performance shows VOC 2.4 V room temperature and 1.7 operating 300x suns. EQE measurements show little decrease up 500 Repeated indicate device be thermally robust.
The design and construction of a high resolution modular x-ray computed tomography (XCT) system is described. approach for meeting specified set performance goals tailored toward experimental versatility highlighted. instrument unique in its detector source configuration, both which enable elevated optimization spatial temporal resolution. process component selection provided. selected components are specified, the custom discussed, integration into fully functional XCT outlined. novelty...
A crystal-based timing calibration method is implemented and investigated on a GE PET scanner. This first calculates block-level adjustments using commercially available algorithm, then, based the calculated adjustments, derives crystal-level needed within each block. Concurrently with time difference acquisition for block-pair adjustment, differences are also accumulated all crystals The crystal averages from represent among these crystals. set to correct both block variations. minimize...
A computer model was developed to study the relationship between ventilation-to-perfusion (V/Q) mismatch and development of inert gas arterial-to-alveolar partial pressure differences (a-A differences). Increasing inhomogeneity V/Q ratio is revealed directly as an increase in a-A difference each gas. The quantitative relationships Q vs. distribution fractional solubility plot plot) were studied described. These studies demonstrated that for log normally distributed ratios, area under...
GaSb and alloys based on the 6.1 Å family can be grown metamorphically substrates such as GaAs allowing for realization of several multijunction solar cell designs. This paper investigates molecular beam epitaxy growth, crystal quality, device performance Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Sb-based single-junction cells substrates. The focus is optimization growth Sb...
Abstract InGaN films have been grown over an In‐rich composition range using a novel growth technique utilizing energetic N‐atoms as the active species. A series of wide substrate temperatures show how film properties improve temperature is lowered. Under optimized conditions, showing excellent compositional uniformity, high degree crystallinity, bright band edge photoluminescence, and smooth surface morphologies spanning In compositions can be obtained. The results emphasize importance N...
Abstract Indium nitride is of interest as a small band gap material for hot carrier solar cells and alloying III‐Nitrides in conventional cells. Growth photovoltaic device quality InN on cost effective sapphire wafers challenging. Lattice mismatch between indium (∼25%) makes growth epitaxial crystals with low crystalline imperfection problematic. films promising XRD results were grown by MBE using well‐aligned AlN buffer layer to grow substrates. Crystal quality, analyzed HRXRD, gives...
Tomographic images of gamma ray sources have been obtained by the use a one-dimensional pseudorandom aperture and computerized digital reconstruction. The binary code is laid out on surface cylinder. source to be imaged must located within cylinder detectors are placed outside facing inward. length matched circumference so that its rotation provides complete time modulation for each source-detector combination. Counts from detector separately stored as function phase angle. Subsequent...
Two series of In-rich InGaN films with compositions ∼25% and ∼35% In, grown over a substrate temperature range from 490 to 620 °C, show how the film properties improve as growth is lowered below InN decomposition ∼550 °C in vacuum. These have been using novel technique utilizing energetic N atoms active species. Under N-rich conditions, these compositional uniformity, crystallinity, band edge photoluminescence, surface morphology are improved temperatures reduced. The results emphasize...
The ability of focused collimators to achieve both high sensitivity and resolution at depth makes them highly desirable for SPECT imaging. Tomographic systems with stationary detector rings are known have the advantages simplicity, stability tolerance variations in response. We combined these two features design a multidetector ring system unique modular collimator brain In manner similar that employed by 4th generation CT scanners, each unit acquires set fan beam projection data while...
In recent years the development of heterojunction silicon based solar cells has gained much attention, lead largely by efforts Panasonic's HIT cell. The success cell prompts scientific exploration other thin film layers, besides industrially accepted amorphous silicon. band gap, mobilities, and electron affinity GaN make it an interesting candidate to solve problems parasitic absorption while selectively extracting electrons. Using a novel MBE growth technique, films have been deposited at...
SPRINT is a transaxial tomograph for use with single photon emitting nuclides. It consists of an aperture cylinder surrounded by ring NaI(Tl) detectors. The singles count rate each detector correlated the position. This provides view image plane activity distribution from detector's perspective. These views are then combined to form slice image. Preliminary operation device has recently been accomplished. structure and calibration procedures defined. statistical behavior data agrees...
A new whole-body PET scanner from General Electric (Discovery ST) is based on 6/spl times/6 BGO block detector using quad photo multipliers and utilizes a state of the art data acquisition system. The consists 280 units in ring structure. Each unit photomultiplier. DST has high sensitivity compared to other available scanners. This paper presents characterization parameters including energy resolution, quality position maps, temperature dependence, timing resolution. several production...
SPRINT (Single Photon RINg Tomograph) is a multiple detector single photon ring imaging device for radionuclides developed at The University of Michigan. employs circular coded aperture to minimize mechanical motion while maximizing efficiency. A one dimensional pseudorandom used that provides transverse section tomography the human head. 78 locations are equally spaced around ring. Gamma rays incident upon NaI(Tl) detectors energy selected and counted by microprocessor controlled data...
Crystalline silicon technology is expected to remain the leading photovoltaic industry workhorse for decades. We present here objectives and workplan of a recently launched project funded by U.S. Department Energy through Foundational Program Advance Cell Efficiency II (FPACE II), which aims at crystalline an efficiency breakthrough. The will tackle fundamental approach materials design, defect engineering, device simulations growth characterization. Among main novelties, implementation...