Electronic Devices and Semiconductor Manufacturing Commons^™

Exfoliation, Synthesis, And Characterization Of Nanoscale Te, Takayuki Hironaka

Graduate Theses and Dissertations

Since the experimental discovery of graphene, two dimensional materials have enjoyed more attention and emphasis in academic research than nanowires, but the latter are an important area of study for creating 1D materials, or single atom chains, the next generation materials for advancing electronic devices. Atomically thin layers can be generated from 2D materials with weak bonds in one direction, and by applying this concept to one dimensional weakly bonded materials, we hypothesize that single atom chains with atomic-scale diameters may be produced. Tellurium (Te) and selenium (Se) have lattices consisting of spiral chains oriented along the c-axis, and each …

Gesn Thin Film Epitaxy And Quantum Wells For Optoelectronic Devices, Perry Christian Grant

Graduate Theses and Dissertations

Group IV photonics is an effort to generate viable infrared optoelectronic devices using group IV materials. Si-based optoelectronics have received monumental research since Si is the heart of the electronics industry propelling our data driven world. Silicon however, is an indirect material whose optical characteristics are poor compared to other III-IV semiconductors that make up the optoelectronics industry. There have been major efforts to integrate III-V materials onto Si substrates. Great progress on the integration of these III-V materials has occurred but incompatibility with CMOS processing has presented great difficulty in this process becoming a viable and cost-effective solution. Germanium …

Investigation Of A Gan-Based Power Supply Topology Utilizing Solid State Transformer For Low Power Applications, Akrem Mohamed Elrajoubi

Graduate Theses and Dissertations

Gallium nitride (GaN) power devices exhibit a much lower gate capacitance for a similar on-resistance than its silicon counterparts, making it highly desirable for high-frequency operation in switching converters, which leads to their significant benefits on power density, cost, and system volume. High-density switching converters are being realized with GaN power devices due to their high switching speeds that reduce the size of energy-storage circuit components. The purpose of this dissertation research is to investigate a new isolated GaN AC/DC switching converter based on solid-state transformer configuration with a totem-pole power factor corrector (PFC) front-end, a half-bridge series-resonant converter (SRC) …

Stability Analysis Of A High-Power Microgrid, David Manuel Carballo Rojas

Graduate Theses and Dissertations

The objective of this thesis is to perform the modeling and stability analysis of a high-power microgrid with multiple parallel-and grid connected voltage source converters using the system parameters from the high-power microgrid testbed at the National Center for Reliable Electric Power Transmission (NCREPT) at the University of Arkansas in order to identify, minimize, if not eliminate, the potential instabilities that can affect the proper operation of the microgrid testbed. To achieve this objective, the mathematical modeling of the high-power microgrid considering the adverse effects of resonances due to interactions among the converter LCL output filters is presented and analyzed. …

Fabrication And Characterization Of Electrochemical Glucose Sensors, Mohammed Marie

Graduate Theses and Dissertations

Electrochemical sensors based on the nanostructure of the semiconductor materials are of tremendous interest to be utilized for glucose monitoring. The sensors, based on the nanostructure of the semiconductor materials, are the third generations of the glucose sensors that are fast, sensitive, and cost-effect for glucose monitoring.

Glucose sensors based on pure zinc oxide nanorods (NRs) grown on different substrates, such ITO, FTO, and Si/SiO2/Au, were investigated in this research. Silicon nanowire (NW)- based glucose sensors were also studied. First, an enzyme-based glucose sensor was fabricated out of glass/ITO/ZnO NRs/BSA/GOx/nafion membrane. The sensor was tested amperometrically at different glucose concentrations. …

Growth And Behaviors Of Inn/Gan Multiple Quantum Wells By Plasma-Assisted Molecular Beam Epitaxy, Chen Li

Graduate Theses and Dissertations

Fully realizing the potential of InGaN semiconductors requires high quality materials with arbitrary In-content. To this date the growth of In-rich InGaN films is still challenging since it suffers from the low growth temperatures and many detrimental alloying problems. InN/GaN multiple quantum wells (MQWs) and super lattices (SLs) are expected to be promising alternatives to random InGaN alloys since in principle they can achieve the equivalent band gap of InGaN random alloys with arbitrarily high In-content and at the same time bypass many growth difficulties.

This dissertation focuses on studying the growth mechanisms, structural properties and energy structures of InN/GaN …

Comparative Study Of Power Semiconductor Devices In A Multilevel Cascaded H-Bridge Inverter, Kenneth Mordi

Graduate Theses and Dissertations

This thesis compares the performance of a nine-level transformerless cascaded H-bridge (CHB) inverter with integrated battery energy storage system (BESS) using SiC power MOSFETs and Si IGBTs. Two crucial performance drivers for inverter applications are power loss and efficiency. Both of these are investigated in this thesis. Power devices with similar voltage and current ratings are used in the same inverter topology, and the performance of each device is analyzed with respect to switching frequency and operating temperature. The loss measurements and characteristics within the inverter are discussed. The Saber® simulation software was used for the comparisons. The power MOSFET …

High-Sn-Content Gesn Alloy Towards Room-Temperature Mid Infrared Laser, Wei Dou

Graduate Theses and Dissertations

Si photonics is a rapidly expanding technology that integrates photonic circuits onto a Si substrate. The integration of Si electronics and photonics has been a successful technology for a wide range of applications. Group-IV alloy GeSn has drawn great attentions as a complementary metal–oxide–semiconductor compatible optoelectronic material for Si photonics. The devices based on GeSn alloy could be monolithically integrated into well-established and high-yield Si integrated circuits, which is favorable for chip-scale Si photonics featuring smaller size, lower cost, and higher reliability.

The relaxed GeSn with high material quality and high Sn composition is highly desirable to cover mid-infrared wavelength. …

Si-Based Germanium Tin Photodetectors For Short-Wave And Mid-Wave Infrared Detections, Thach Pham

Graduate Theses and Dissertations

The demand of light-weight and inexpensive imaging system working in the infrared range keeps increasing for the last decade, especially for civil applications. Although several group IV materials such as silicon and germanium are used to realize detectors in the visible and near infrared region, they are not the efficient approach for imaging system in the short-wave infrared detection range and beyond due to bandgap limit. On the other hand, this market is heavily relied upon mature technology from III-V and II-VI elements over years, which are costly to growth and incompatible with available Si complementary metal-oxide-semiconductor (CMOS) foundries. This …

Design, Fabrication, And Characterization Of Novel Optoelectronic Devices For Near-Infrared Detection, Ahmad Nusir

Graduate Theses and Dissertations

Investigating semiconductor materials and devices at the nanoscale has become crucial in order to maintain the exponential development in today’s technology. There is a critical need for making devices lower in power consumption and smaller in size. Nanoscale semiconductor materials provide a powerful platform for optoelectronic device engineers. They own interesting properties which include enhanced photoconductivity and size-tunable interband transitions.

In this research, different types of nanostructures were investigated for optoelectronic devices: nanocrystals, nanowires, and thin-films. First, lead selenide nanocrystals with narrow bandgap were synthesized, size-tailored, and functionalized with molecular ligands for the application of uncooled near-infrared photodetectors. The devices …

Glucose Level Estimation Based On Invasive Electrochemical, And Non-Invasive Optical Sensing Methods, Sanghamitra Mandal

Graduate Theses and Dissertations

The purpose of this research is to design and fabricate sensors for glucose detection using inexpensive approaches. My first research approach is the fabrication of an amperometric electrochemical glucose sensor, by exploiting the optical properties of semiconductors and structural properties of nanostructures, to enhance the sensor sensitivity and response time. Enzymatic electrochemical sensors are fabricated using two different mechanisms: (1) the low-temperature hydrothermal synthesis of zinc oxide nanorods, and (2) the rapid metal-assisted chemical etching of silicon (Si) to synthesize Si nanowires. The concept of gold nano-electrode ensembles is then employed to the sensors in order to boost the current …

Design, Fabrication, And Characterization Of All-Inorganic Quantum Dot Light Emitting Diodes, Ramesh Vasan

Graduate Theses and Dissertations

Quantum dot light emitting diodes are investigated as a replacement to the existing organic light emitting diodes that are commonly used for thin film lighting and display applications. In this, all-inorganic quantum dot light emitting diodes with inorganic quantum dot emissive layer and inorganic charge transport layers are designed, fabricated, and characterized. Inorganic materials are more environmentally stable and can handle higher current densities than organic materials. The device consists of CdSe/ZnS alloyed core/shell quantum dots as the emissive layer and metal oxide charge transport layer. The charge transport in these devices is found to occur through resonant energy transfer …

Application Of Modular Multilevel Converters (Mmc) Using Phase-Shifted Pwm And Selective Harmonic Elimination In Distribution Systems, Thouhidul Islam

Graduate Theses and Dissertations

Reducing the size and weight of a power electric system is a prodigious challenge to researchers as the development of the latest technologies emerge in the field of electrical engineering. A similar urge is there to develop a light-weight mobile power substation (MPS) to use in the electric power distribution systems during emergency conditions. This thesis proposes a power electronics based solution using the modular multilevel converter (MMC) topology to design the MPS system. The market-available power semiconductor devices are analyzed and suitable devices are selected to design the system. The phase-shifted pulse width modulation (PS-PWM) and selective harmonic elimination …

Evaluation Of Terahertz Imaging For Breast Cancer Detection Using Image Morphing, Tanny Andrea Chavez Esparza

Graduate Theses and Dissertations

This thesis proposes the use of a mesh morphing algorithm for the quantitative evaluation of terahertz (THz) images. This work differs from traditional evaluation methods based on qualitative evaluation because it provides a fair and quantitative measurement of the THz imaging system's performance. The objective of the algorithm is to match the alignment, shape, and resolution of the THz and reference pathology images. Therefore, the proposed morphing method provides a pathology reference for a pixel-by-pixel evaluation of the region classification in the THz image. To achieve this, the morphing algorithm aligns the images using the Pearson's correlation coefficient and reshapes …