Engineering Commons^™

Electrophertic Deposition And Characterization Of Molybdenum Disulfide On Silicon Substrates, Alex J. Young

LSU Doctoral Dissertations

The electrical characteristics of 2D materials such as high electron mobility and current density are of great interest to various fields from optoelectronics to renewable energy. Researchers have focused their efforts on transition metal dichalcogenides (TMDCs) due to their direct energy band gap. One such TMDC that has garnered much attention is molybdenum disulfide (MoS2). MoS2 has electrical properties comparable to graphene and is a TMDC with characteristics amenable to applications such as solar cells and sensors. Commonly deposited through time-consuming and complex deposition methods such as chemical vapor deposition (CVD), the viability of MoS2 as an electronic material will …

An Accurate And Efficient Electro-Thermal Compact Model Of Sic Power Mosfet Including Third Quadrant Behavior, Arman Ur Rashid

Graduate Theses and Dissertations

Due to narrower bandgap and lower critical electric field, silicon (Si) power devices have reached their limit in terms of the maximum blocking voltage capability. Exploiting this limitation, wide bandgap devices, namely silicon carbide (SiC) and gallium nitride (GaN) devices, are increasingly encroaching on the lucrative power electronics market. Unlike GaN, SiC devices can exploit most of the established fabrication techniques of Si power devices. Having substrate of the same material, vertical device structures with higher breakdown capabilities are feasible in SiC, unlike their GaN counterpart. Also, the excellent thermal conductivity of SiC, compared to GaN and Si, let SiC …

Characterization, Analysis, And Application Of Wbg Power Devices For Future Power Conversion Systems, Ali Mahmoud Salman Al-Bayati

Electronic Theses and Dissertations

Semiconductor power devices are the most momentous constituents of any power converter system. Fast switching, compactness, high performance and efficiency, and high temperature operation are the exacting challenges experienced by conventional silicon (Si) power device based power converters in many applications. In this dissertation, the wide bandgap (WBG) power devices are studied and used to transcend the limitations imposed by the Si power devices. It mainly focuses on characterization and analysis of the behavior of WBG power devices as well as design and development of efficient, high performance, and reliable dc–dc power converters based on WBG technology. First, using computer …

High-Temperature Optoelectronic Device Characterization And Integration Towards Optical Isolation For High-Density Power Modules, Syam Madhusoodhanan

Graduate Theses and Dissertations

Power modules based on wide bandgap (WBG) materials enhance reliability and considerably reduce cooling requirements that lead to a significant reduction in total system cost and weight. Although these innovative properties lead power modules to higher power density, some concerns still need to be addressed to take full advantage of WBG-based modules. For example, the use of bulky transformers as a galvanic isolation system to float the high voltage gate driver limits further size reduction of the high-temperature power modules. Bulky transformers can be replaced by integrating high-temperature optocouplers to scale down power modules further and achieve disrupting performance in …

Thermal Transport Modeling Of Semiconductor Materials From First Principles, Aliya Qureshi

Masters Theses

Over the past few years, the size of semiconductor devices has been shrinking whereas the density of transistors has exponentially increased. Thus, thermal management has become a serious concern as device performance and reliability is greatly affected by heat. An understanding of thermal transport properties at device level along with predictive modelling can lead us to design of new systems and materials tailored according to the thermal conductivity. In our work we first review different models used to calculate thermal conductivity and examine their accuracy using the experimentally measured thermal conductivity for Si. Our results suggest that empirically calculated rates …

Interfacial Contact With Noble Metal - Noble Metal And Noble Metal - 2d Semiconductor Nanostructures Enhance Optical Activity, Ricardo Raphael Lopez Romo

Graduate Theses and Dissertations

Noble metal nanoparticles and two-dimensional (2D) transition metal dichalcogenide (TMD) crystals offer unique optical and electronic properties that include strong exciton binding, spin-orbital coupling, and localized surface plasmon resonance. Controlling these properties at high spatiotemporal resolution can support emerging optoelectronic coupling and enhanced optical features. Excitation dynamics of these optical properties on physicochemically bonded mono- and few-layer TMD crystals with metal nanocrystals and two overlapping spherical metal nanocrystals were examined by concurrently (i) DDA simulations and (ii) far-field optical transmission UV-vis spectroscopic measurements. Initially, a novel and scalable method to unsettle van der Waals bonds in bulk TMDs to prepare …

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 …

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 …

Si-Based Germanium Tin Semiconductor Lasers For Optoelectronic Applications, Sattar H. Sweilim Al-Kabi

Graduate Theses and Dissertations

Silicon-based materials and optoelectronic devices are of great interest as they could be monolithically integrated in the current Si complementary metal-oxide-semiconductor (CMOS) processes. The integration of optoelectronic components on the CMOS platform has long been limited due to the unavailability of Si-based laser sources. A Si-based monolithic laser is highly desirable for full integration of Si photonics chip. In this work, Si-based germanium-tin (GeSn) lasers have been demonstrated as direct bandgap group-IV laser sources. This opens a completely new avenue from the traditional III-V integration approach. In this work, the material and optical properties of GeSn alloys were comprehensively studied. …

Study Of Direct Semiconductor Materials For An Optically Controlled Switch, Sung Taek Ko

Electrical & Computer Engineering Theses & Dissertations

A model for a bulk GaAs photoconductive switch has been developed and solved to determine the performance of the device in closing and opening switch applications. The GaAs material has been characterized by deep level transient spectroscopy (DLTS). Two electron traps (EL2 and EL5) and one hole trap (Cu_B} have been detected and were included in the model. Simulation studies are performed on several GaAs switch systems composed of different combinations and density of deep levels to investigate the influence of deep traps in a photoconductive switch system. The electron occupancy of each deep trap is traced in …