Triple-Junction Solar Cells : In Parallel., 2019 University of Louisville
Triple-Junction Solar Cells : In Parallel., Levi C Mays
Electronic Theses and Dissertations
This paper looks into the current inefficiency of solar cells and attempts a few alternative solar cell structures in order to provide a more effective source of renewable energy. Currently, multi-junction solar cells are being developed to capture the sun’s light more efficiently. One of the ideas in this paper is to add a window to see if the addition of such a layer into a junction will increase the voltage while maintaining nearly the same current output. Central to this paper is the rearranging of the conducting layers of the multi-junction cell so that the junctions can be ...
First Demonstration Of Ultra-Thin Sige-Channel Junctionless Accumulation-Mode (Jam) Bulk Finfets On Si Substrate With Pn Junction-Isolation Scheme, 2019 Missouri University of Science and Technology
First Demonstration Of Ultra-Thin Sige-Channel Junctionless Accumulation-Mode (Jam) Bulk Finfets On Si Substrate With Pn Junction-Isolation Scheme, Donghyun Kim, Tae Kyun Kim, Young Gwang Yoon, Byeong Woon Hwang, Yang-Kyu Choi, Byung Jin Cho, Seok-Hee Lee
DongHyun (Bill) Kim
A SiGe-channel junctionless-accumulation-mode (JAM) PMOS bulk FinFETs were successfully demonstrated on Si substrate with PN junction-isolation scheme for the first time. The JAM bulk FinFETs with fin width of 18 nm exhibits excellent subthreshold characteristics such as subthreshold swing of 64 mV/decade, drain-induced barrier lowering (DIBL) of 40 mV/V and high Ion/Ioff current ratio ( > 1 x 105). The change of substrate bias from 0 to 5 V leads to the threshold voltage shift of 53 mV by modulating the effective channel thickness. When compared to the Si-channel bulk FinFETs with fin width of 18 ...
Dc-Dc Converter For Electric Vehicle, 2019 California Polytechnic State University, San Luis Obispo
Dc-Dc Converter For Electric Vehicle, Jason Y. Zhou, Nicholas James Mah
In this work, a DC-DC converter is designed for an electric vehicle. The DC-DC converter is designed to provide 500W with a 200-400V input and a 12-15V adjustable output. Electric vehicle sales are beginning to increase in popularity and the need for DC-DC converters to siphon power from the tractive system is not yet fully satisfied, especially for single-seater class vehicles. Additionally, improving performance in efficiency without sacrificing wide input voltage range can benefit future DC-DC converter designs. In the end, a forward active clamp DC-DC converter is designed and tested. Additionally, spreadsheet calculators, LTSpice simulations, and Matlab scripts were ...
High Frequency Constraints On The Layout Of Wide Band Gap-Based Power Electronic Assemblies Within Shielded Enclosures, 2019 University of Wisconsin-Milwaukee
High Frequency Constraints On The Layout Of Wide Band Gap-Based Power Electronic Assemblies Within Shielded Enclosures, Jonathan Hajime Itokazu
Theses and Dissertations
Since its integration into power electronic converters, the value proposition of wide band
gap semiconductors has yet to be holistically realized due to the high frequency effects associated with increased switching speeds. The United States Navy’s Smart Ship System
Design (S3D) platform enables the investigation of wide band gap-based devices in shipboard Medium Voltage Direct Current (MVDC) Integrated Power and Energy Systems
(IPES) through the use of metaheuristic model-based scaling laws. These physics-based
scaling laws are produced from a virtual prototyping approach which takes into account the
discrete building blocks associated with multi-cell based power conversion and distribution
Research Of Electro-Optical Effect In Metal Halide Perovskites By Fabry-Perot Interometer Method, 2019 Washington University in St. Louis
Research Of Electro-Optical Effect In Metal Halide Perovskites By Fabry-Perot Interometer Method, Hanxiang Yin
Engineering and Applied Science Theses & Dissertations
Perovskites have been investigated a lot by present and reported with outstanding optoelectronic properties. However, so far there is no publications about another important property, the electro-optical (EO) effect which is related to important applications in photolithography. This thesis is mainly mean to calculate the EO constants of one kind of organic perovskite material, CH3NH3PbI3, which has been reported to have good capability of forming film by spin-coating, through the way of putting the film of CH3NH3PbI3 between two layers of metal mirrors to build a Fabry-Perot interferometer and characterizing ...
Characterization Of Hydride Vapor Phase Epitaxy Grown Gan Substrates For Future Iii-Nitride Growth, 2019 University of Arkansas, Fayetteville
Characterization Of Hydride Vapor Phase Epitaxy Grown Gan Substrates For Future Iii-Nitride Growth, Alaa Ahmad Kawagy
Theses and Dissertations
The aim of this research is to investigate and characterize the quality of commercially obtained gallium nitride (GaN) on sapphire substrates that have been grown using hydride vapor phase epitaxy (HVPE). GaN substrates are the best choice for optoelectronic applications because of their physical and electrical properties. Even though HVPE GaN substrates are available at low-cost and create the opportunities for growth and production, these substrates suffer from large macro-scale defects on the surface of the substrate.
In this research, four GaN on sapphire substrates were investigated in order to characterize the surface defects and, subsequently, understand their influence on ...
Optical Response Analysis Of Thz Photoconductive Antenna Using Comsol Multiphysics, 2019 University of Arkansas, Fayetteville
Optical Response Analysis Of Thz Photoconductive Antenna Using Comsol Multiphysics, Jose Isaac Santos Batista
Electrical Engineering Undergraduate Honors Theses
A THz photoconductive antenna consists of antenna pads laid over a photoconductive substrate. These types of antennas are excited through the application of an optical pump (laser), which generates carriers inside the semiconductor. The acceleration and recombination of these carriers produce photocurrent that excites the antenna and generates THz pulse. This thesis focuses on analyzing the optical response of a photoconductive antenna, which consist of the interaction of the incident electric field of a laser pump with the radiating device. It develops the amplitude modulation process of a plane wave of light into a laser pump. It also takes into ...
Experimental And Computational Study On Magnetic Nanowires Of Layered Titanates, 2019 University of Arkansas, Fayetteville
Experimental And Computational Study On Magnetic Nanowires Of Layered Titanates, Caleb Layne Heath
Theses and Dissertations
The intricate nanostructures of layered titanates are unique among nanomaterials due to their easy and inexpensive syntheses. These nanomaterials have been proven valuable for use in industries as varied as energy, water treatment, and healthcare, and can be produced at industrial scales using already existent equipment. They have complex morphology, and surface structure well suited to chemical modification and doping. However, there is a longstanding debate on their lattice structure after the doping. There is a long-unmet need to understand, using both experimental and simulation methods, how dopants alter the clay-like layered crystal structure and associated physical and chemical properties ...
Investigation Of Critical Technologies Of Chemical Vapor Deposition For Advanced (Si)Gesn Materials, 2019 University of Arkansas, Fayetteville
Investigation Of Critical Technologies Of Chemical Vapor Deposition For Advanced (Si)Gesn Materials, Joshua Matthew Grant
Theses and Dissertations
The development of new materials for efficient optoelectronic devices from Group IV elements is the heart of Group IV photonics. This has direct ties to modern technology as the foundation for the electronics industry is silicon. This has driven the development of silicon-based optoelectronics using these other Group IV materials as silicon is a poor optical material due to its indirect band gap when compared to the III-V semiconductors that are used by most of the optoelectronics industry. While efforts have been made to integrate III-V materials onto silicon substrates, the incompatibility with the complementary metal oxide semiconductor process has ...
Urban Underground Infrastructure Monitoring Iot: The Path Loss Analysis, 2019 Purdue University
Urban Underground Infrastructure Monitoring Iot: The Path Loss Analysis, Abdul Salam, Syed Shah
The extra quantities of wastewater entering the pipes can cause backups that result in sanitary sewer overflows. Urban underground infrastructure monitoring is important for controlling the flow of extraneous water into the pipelines. By combining the wireless underground communications and sensor solutions, the urban underground IoT applications such as real time wastewater and storm water overflow monitoring can be developed. In this paper, the path loss analysis of wireless underground communications in urban underground IoT for wastewater monitoring has been presented. It has been shown that the communication range of up to 4 kilometers can be achieved from an underground ...
An Underground Radio Wave Propagation Prediction Model For Digital Agriculture, 2019 Purdue University
An Underground Radio Wave Propagation Prediction Model For Digital Agriculture, Abdul Salam
Underground sensing and propagation of Signals in the Soil (SitS) medium is an electromagnetic issue. The path loss prediction with higher accuracy is an open research subject in digital agriculture monitoring applications for sensing and communications. The statistical data are predominantly derived from site-specific empirical measurements, which is considered an impediment to universal application. Nevertheless, in the existing literature, statistical approaches have been applied to the SitS channel modeling, where impulse response analysis and the Friis open space transmission formula are employed as the channel modeling tool in different soil types under varying soil moisture conditions at diverse communication distances ...
Non-Invasive Beam Monitoring With Harmonic Cavities, 2019 University of New Mexico
Non-Invasive Beam Monitoring With Harmonic Cavities, Brock F. Roberts
Electrical and Computer Engineering ETDs
NON INVASIVE BEAM MONITORING WITH HARMONIC CAVITIES
Brock Franklin Roberts
B.S PHYSICS, UNIVERSITY OF CALIFORNIA DAVIS, 1992
DOCTOR OF PHILOSOPHY IN ELECTRICAL ENGINEERING
UNIVERSITY OF NEW MEXICO, 2019
A cavity designed to have multiple harmonic TM0N0 modes can be used to accurately measure the longitudinal profile of a bunched charged particle beam passing through its bore, non-invasively, and in real time.
Multi-harmonic TM0N0 cavities were designed, constructed, and beamline tested in a variety of experiments at the Thomas Jefferson National Accelerator Facility (TJNAF or Jlab). Measurements with a sampling oscilloscope provided signals that resemble the profile of ...
Intelligent Metasurfaces With Continuously Tunable Local Surface Impedance For Multiple Reconfigurable Functions, Fu Liu, Odysseas Tsilipakos, Alexandros Pitilakis, Anna C. Tasolamprou, Mohammad Sajjad Mirmoosa, Nikolaos V. Kantartzis, Do-Hoon Kwon, Maria Kafesaki, Costas M. Soukoulis, Sergei A. Tretyakov
Ames Laboratory Accepted Manuscripts
Electromagnetic metasurfaces can be characterized as intelligent if they are able to perform multiple tunable functions, with the desired response being controlled by a computer influencing the individual electromagnetic properties of each metasurface inclusion. In this paper, we present an example of an intelligent metasurface that operates in the reflection mode in the microwave frequency range. We numerically show that, without changing the main body of the metasurface, we can achieve tunable perfect absorption and tunable anomalous reflection. The tunability features can be implemented using mixed-signal integrated circuits (ICs), which can independently vary both the resistance and reactance, offering complete ...
Ultrashort Cross-Correlation In The Middle Infrared: A Novel Approach To Standoff Detection, 2019 University of Nebraska-Lincoln
Ultrashort Cross-Correlation In The Middle Infrared: A Novel Approach To Standoff Detection, William Conner Thomas
Theses, Dissertations, and Student Research from Electrical & Computer Engineering
Lasers are a common tool in standoff detection because of their small divergence, large amount of power, and multiple wavelengths available for optical interaction. Optical signatures of targets can be composed of but are not limited to absorption, fluorescence, backscatter, polarization manipulation, and plasma spectra. This work was an investigation of a new signature phenomenon: Dispersion of middle infrared ultrashort laser pulses through gas and vapor phase molecules. Vibrational and rovibrational absorption lines of molecular species affect the spectral phase and spectral amplitude of ultrashort light pulses leading an inititally gaussian temporal profile to become distorted. This dissertation is an ...
Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data, 2019 Missouri University of Science and Technology
Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data, Ryan G. Smith, R. Knight
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Land subsidence as a result of groundwater overpumping in the San Joaquin Valley, California, is associated with the loss of groundwater storage and aquifer contamination. Although the physical processes governing land subsidence are well understood, building predictive models of subsidence is challenging because so much subsurface information is required to do so accurately. For the first time, we integrate airborne electromagnetic data, representing the subsurface, with subsidence data, mapped by interferometric synthetic aperture radar (InSAR), to model deformation. By combining both data sets, we are able to solve for hydrologic and geophysical properties of the subsurface to effectively model the ...
Inverse Design Of Three-Dimensional Nanoantennas For Metasurface Applications, 2019 United States Military Academy
Inverse Design Of Three-Dimensional Nanoantennas For Metasurface Applications, Danny Zhu, Eric B. Whiting, Sawyer D. Campbell, Pingjuan L. Werner, Douglas H. Werner
West Point Research Papers
Recent advances in manufacturing techniques have been made to match the demand for high performance optical devices. To this end, tremendous research activity has been focused on optical metasurfaces as they offer a unique potential to achieve disruptive designs when paired with innovative fabrication techniques and inverse design tools. However, most metasurface designs have revolved around canonical geometries. While these elements are relatively easy to fabricate, they represent only a small portion of the design space, and rarely offer peak performance in transmission, phase range or field of view. In this work, a Lazy Ant Colony Optimization (LACO) technique is ...
Fabrication Of Biased-Magnetorheological Elastomers (B-Mre) Based On Magnetized Ferromagnetic Particles, 2019 University of Nevada, Las Vegas
Fabrication Of Biased-Magnetorheological Elastomers (B-Mre) Based On Magnetized Ferromagnetic Particles, Choonghan Lee, Woosoon Yim
Mechanical Engineering Faculty Publications
Magnetorheological elastomers (MREs), like MR fluids, exploit magnetic forces between ferromagnetic particles to produce a material with instantaneously adjustable properties of stiffness and damping with external magnetic fields. In MREs, the particles are a part of a structured elastomer matrix, and an external magnetic field is applied to achieve an instantaneous change of stiffness due to magnetic forces between particles. A drawback of conventional MREs is its inability of softening (reduce stiffness) under an external field. Many engineering applications need an instant change of its stiffness in both directions, which requires a magnetic bias embedded in the MRE. One way ...
Designing Liquid Crystal For Optoacoustic Detection, 2019 Air Force Institute of Technology
Designing Liquid Crystal For Optoacoustic Detection, Michael T. Dela Cruz
Theses and Dissertations
This research impacts the development of a cost-saving, on-chip device that can replace a wide range of costly, bulky sensors for commercial and defense applications. In particular, the goals of this work were to design and test a sensor that uses the optical properties of liquid crystal (LC) to detect acoustic waves. This began with developing a method to fine-tune the optical features of the liquid crystal. Statistical analysis of select experimental variables, or factors, lead to ideal settings of those variables when creating the sensor. A two-factor and three-factor experiment were separately conducted and analyzed as a preliminary demonstration ...
A Focal Plane Array And Electronics Model For Cmos And Ccd Sensors In The Afit Sensor And Scene Emulation Tool (Asset), 2019 Air Force Institute of Technology
A Focal Plane Array And Electronics Model For Cmos And Ccd Sensors In The Afit Sensor And Scene Emulation Tool (Asset), Fernando D. Fernandez
Theses and Dissertations
Electro-optical and infrared (EO/IR) sensor models are useful tools that can facilitate understanding a system's behavior without expensive and time-consuming testing of an actual system. EO/IR models are especially important to the military industry where truth data is required but is sometimes impractical to obtain through experimentation due to expense or difficulties in procuring hardware. This work describes implementation of a focal plane array (FPA) model of charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) photodetectors as a component in the Air Force Institute of Technology (AFIT) Sensor and Scene Emulation Tool (ASSET). The FPA model covers ...
Electromagnetic Characterization Of Conductor-Backed Media Using Stepped Rectangular Waveguide, 2019 Air Force Institute of Technology
Electromagnetic Characterization Of Conductor-Backed Media Using Stepped Rectangular Waveguide, Avian Y. Hughes
Theses and Dissertations
A new single stepped-iris waveguide technique is used to nondestructively determine the permittivity and permeability of conductor-backed media. This thesis will demonstrate a proof-of-concept that obtains two independent reflection measurements with a magnetic radar absorbing material (magRAM). Using a two measurement procedure, in which, the first measurement will apply a single rectangular waveguide to a known conductor-backed absorbing material under test (MUT) and the second measurement will insert a stepped-iris in between the single rectangular waveguide and MUT reducing the aperture to retrieve two independent electromagnetic properties (i.e. permittivity and permeability). The theoretical reflection coefficients are obtained using a ...