Fabrication And Characterization Of A Palladium/Porous Silicon Layer, 2013 California Polytechnic State University, San Luis Obispo
Fabrication And Characterization Of A Palladium/Porous Silicon Layer, Nicholas Hong Lui
Master's Theses
When porous silicon is plated with a catalytic metal, the two materials can act together as a single entity whose electrical properties are sensitive to its environment – the sensing component of an electrochemical gas sensor. Etching pores into silicon is an electrochemical process; and which type of doped silicon used is one of its key parameters. For nearly all reported porous silicon gas sensors, the silicon has been of the p-doped variety – because p-doped porous etching is better understood and the layers that result from it are more predictable – despite n-doped silicon having potentially significant benefits in …
Growth And Properties Of Boron Phosphide Films On Silicon Carbide, 2013 University of Tennessee, Knoxville
Growth And Properties Of Boron Phosphide Films On Silicon Carbide, Guoliang Li
Doctoral Dissertations
Boron phosphide (BP) is a promising material for the development of high-efficiency solid-state thermal neutron detectors. However, the synthesis of good-quality BP film had been an obstacle. In this work, silicon carbide (SiC) substrates with vicinal steps instead of the conventional silicon (Si) substrates are used for BP growths. A series of growth experiments are performed and good-quality epitaxial BP films are successfully obtained and for the first time fully characterized. The optimized growth conditions are established, the film growth mechanism and defect origination mechanism are interpreted after an integrated experimental and theoretical study.
The Design And Fabrication Of An Electrostatically Actuated Diaphragm With A Silicon-On-Insulator Wafer, 2013 California Polytechnic State University, San Luis Obispo
The Design And Fabrication Of An Electrostatically Actuated Diaphragm With A Silicon-On-Insulator Wafer, Elizabeth L. Brooks
Master's Theses
Electrostatically actuated silicon membranes were designed, modeled, fabricated, and characterized. The intended application was for use in a microspeaker. Fabrication issues necessitated the use of thick diaphragms with a large gap between the electrodes. The devices did not function as speakers but did show actuation with a high DC voltage. Device dimensions were chosen by examining membrane mechanics, testing the processing steps required for device fabrication, and modeling with COMSOL. Several adhesives were researched to fabricate the device sidewalls, including BCB, PMMA, and TRA-Bond F112. A method for patterning PMMA through photolithography was found using a scanning electron microscope. Masks …
Optical And Mechanical Investigation Of Inas /Gaas Quantum Dots Solar Cells And Inas Nanowires For The Application Of Photovoltaic Device, 2013 Rochester Institute of Technology
Optical And Mechanical Investigation Of Inas /Gaas Quantum Dots Solar Cells And Inas Nanowires For The Application Of Photovoltaic Device, Yushuai Dai
Theses
Self-assembled quantum dots (QDs) and nanowires (NWs) are currently the subjects of extensive study due to their promising applications in optoelectronic devices. In order to enhance understanding of the short circuit current improvement in InAs/GaAs quantum dots solar cell (QDSC), the mechanisms of carrier escape by thermal activation and tunneling from InAs quantum dots (QDs) confinements in InAs/GaAs QDSCs are investigated. The fitted activation energy of electrons from temperature dependent photoluminescence (TDPL) is 114 meV. Using this fitted activation energy, calculated thermal escape time and tunneling time of electrons from the ground state of the QDs are 10-12 seconds and …
Fe, Co And Ni Adatoms Adsorbed On Silicene: A Dft Study, 2013 Illinois Mathematics and Science Academy
Fe, Co And Ni Adatoms Adsorbed On Silicene: A Dft Study, Kent Gang '14, Siva Gangavarapu '14, Matthew Deng '14, Glenn W. "Max" Mcgee, Ron Hurlbut, Michael Lee Dao Kang, Sean Ng Peng Nam, Harman Johll, Tok Eng Soon
Student Publications & Research
Two-dimensional materials have attracted much research attention given their intriguing properties. The latest member of this class of materials is silicene. In this work, we investigate the adsorption of Fe, Co and Ni adatoms on silicene using plane-wave density functional theory calculations within the Perdew-Burke-Ernzerhof parameterization of the generalized gradient approximation for the exchange-correlation potential. In particular, we calculate the binding energy, magnetization, and projected electronic configurations of these adatoms adsorbed at different sites on the silicene. Our calculations show that the hole site (i.e. in the centre of a hexagonal-like arrangement of Si atoms) is the most stable configuration …
Constructing And Optimizing A Single Wafer Solar Cell Array In The Microfabrication Lab At California Polytechnic State University At San Luis Obispo, 2013 California Polytechnic State University, San Luis Obispo
Constructing And Optimizing A Single Wafer Solar Cell Array In The Microfabrication Lab At California Polytechnic State University At San Luis Obispo, Rod Marstell
Master's Theses
CONSTRUCTING AND OPTIMIZING A SINGLE WAFER SOLAR CELL ARRAY IN THE MICROFABRICATION LAB AT CALIFORNIA POLYTECHNIC STATE UNIVERSITY AT SAN LUIS OBISPO
Solar cells are more and more becoming a significant source of energy in the world today. They are used to power entire buildings as well as small devices and everything in between, and are utilized all around the world. Smaller solar devices, such as hearing aid battery chargers, cost a lot of money relative to the monetary wealth in third-world countries. For this purpose, a less expensive, more efficient solar cell array should be developed.
This study contains …
Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, 2013 California Polytechnic State University - San Luis Obispo
Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, Logan M. Grimes
Materials Engineering
Fluorescence profiles of quantum dots (QDs) were characterized to select the ideal QDs for encapsulation in phospholipids for use as biomarkers to selectively adhere to cancer cells. QDs were synthesized and extracted 0, 30, 60, and 90 seconds after precursor compounds were mixed. These extractions were isolated by extraction time. Portions from each vial were coated in a zinc sulfide shelling procedure, leaving at least half of the QD solution unshelled. These samples were characterized over four days to monitor fluctuations in fluorescence. This was done utilizing an Ocean Optics spectrometer in conjunction with Spectra Suite software. The central wavelength, …
Design And Implementation Of A Micro Force Displacement System, 2013 California Polytechnic State University - San Luis Obispo
Design And Implementation Of A Micro Force Displacement System, Evan Cate
Materials Engineering
The design and implementation of a micro-force displacement system was completed to test various Micro-Electro-Mechanical Systems (MEMS) devices including silicon diaphragms and cantilevers. The system utilizes a World Precision Instruments Fort 10g force transducer attached to a World Precession Instruments TBM4M amplifier. A Keithley 2400 source meter provided data acquisition of the force component of the system. A micro prober tip was utilized as the testing probe attached to the force transducer with a tip radius of 5um. The displacement of samples was measured using a Newport M433 linear stage driven by a Newport ESP300 motion controller (force readings at …
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, 2013 California Polytechnic State University - San Luis Obispo
Development Of A High Precision Quantum Dot Synthysis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Cell, Harry Lafferty, Jonny Hoadley
Materials Engineering
Quantum dots show great potential for use as spectral converters in solar cells, lighting applications and biological imaging. These applications require precise control of quantum dot size to maximize performance. The fluorescence profile of quantum dots in solution correlates directly with particle size. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow through cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17± 1°C. Using an NE-300® syringe pump, the solution was pumped through a microfluidic reactor …
Application Of Quantum Dots Onto Glass Wafers As A Feasibility Test For The Spectral Down Conversion Of Uv Light For Solar Cells, 2013 California Polytechnic State University - San Luis Obispo
Application Of Quantum Dots Onto Glass Wafers As A Feasibility Test For The Spectral Down Conversion Of Uv Light For Solar Cells, Anthony Fong
Materials Engineering
Quantum dots have the ability to convert high energy photons into multiple lower energy photons. Down conversion of such high energy photons from sources such as UV light can be beneficial for applications on solar cells which waste much of the energy in the form of thermalization. To test this theory, a solar cell was hooked up to an Amprobe Solar Analyzer and tests were run to compare power output with and without the presence of quantum dots. Additionally, quantum dots were spin coated onto a glass wafer to determine its adhesion ability. Spectrometer readings were taken of the wafer …
Scanning Tunneling Spectroscopy Under Atmospheric Conditions To Characterize A Tungsten Tip Stm System For Use With Hydrogen Desorption, 2013 California Polytechnic State University - San Luis Obispo
Scanning Tunneling Spectroscopy Under Atmospheric Conditions To Characterize A Tungsten Tip Stm System For Use With Hydrogen Desorption, Ross Gregoriev
Materials Engineering
The electrical surface structure of (111) n-type silicon was investigated through the use of scanning tunneling spectroscopy (STS) to develop a model to determine oxide presence on a passivated silicon surface. I-V curves were obtained with a scanning tunneling microscope (STM) using a tungsten tip on various locations of passivated silicon while the passivation layer desorbed from the surface under standard atmospheric conditions. The derivative (dI/dV) of these curves then revealed the electronic structure of the surface of the sample. Through these scans, it was determined the system was operating in the same mode as a Shockley diode. The separation …
The Fabrication & Characterization Of An Electrokinetic Microfluidic Pump From Su-8, A Negative Epoxy-Based Photoresist, 2013 California Polytechnic State University, San Luis Obispo
The Fabrication & Characterization Of An Electrokinetic Microfluidic Pump From Su-8, A Negative Epoxy-Based Photoresist, Nash Anderson
Master's Theses
Microfluidics refers to manipulation, precise control, and behavior of fluids at the micro and nanoliter scales. It has entered the realm of science as a way to precisely measure or mix small amounts of fluid to perform highly controlled reactions. Glass and polydimethylsiloxane (PDMS) are common materials used to create microfluidic devices; however, glass is difficult to process and PDMS is relatively hydrophobic. In this study, SU-8, an epoxy based (negative) photoresist was used to create various electrokinetic microfluidic chips. SU-8 is commonly used in microelectromechanical design. Spin coating of various SU-8 formulations allows for 1 μm to 100 μm …
Characterization And Modeling Of An O-Band 1310 Nm Sampled-Grating Distributed Bragg Reflector (Sg-Dbr) Laser For Optical Coherence Tomography (Oct) Applications, 2013 California Polytechnic State University, San Luis Obispo
Characterization And Modeling Of An O-Band 1310 Nm Sampled-Grating Distributed Bragg Reflector (Sg-Dbr) Laser For Optical Coherence Tomography (Oct) Applications, Desmond Charles Talkington
Master's Theses
In this project, the performance aspects of a new early generation 1310 nm Sampled-Grating Distributed Bragg Reflector (SG-DBR) semiconductor laser are investigated. SG-DBR lasers are ideal for Source Swept Optical Coherence Tomography (SS-OCT), a Fourier-Domain based approach for OCT, necessitating a tunable wavelength source. Three internal sections control the frequency output for tuning, along with two amplifiers for amplitude control. These O-band SG-DBR devices are now being produced in research quantities. SG-DBR lasers have been produced at 1550 and 1600 nm for some times. Fundamental questions regarding the performance of the 1310 nm devices must be quantified. Standard metrics including …
Band Gap Narrowing Of Titanium Dioxide (Tio2) Nanocrystals By Electrochemically Active Biofilm And Their Visible Light Activity, 2013 Universiti Brunei Darussalaam
Band Gap Narrowing Of Titanium Dioxide (Tio2) Nanocrystals By Electrochemically Active Biofilm And Their Visible Light Activity, S. Kalathil, Mohammad Mansoob Khan Dr, Sajid A. Ansari, M. H. Cho, J. Lee
Dr. Mohammad Mansoob Khan
We report a simple biogenic-route to narrow the band gap of TiO2 nanocrystals for visible light application by offering a greener method. When an electrochemically active biofilm (EAB) was challenged with a solution of Degussa-TiO2 using sodium acetate as electron donor, greyish blue-colored TiO2 nanocrystals were obtained. Band gap study showed that band gap of the modified TiO2 nanocrystals was significantly reduced (Eg = 2.85 eV) compared to the unmodified white Degussa TiO2 (Eg = 3.10 eV).
Novel Bimetallic Plasmonic Nanomaterials, 2013 University of Tennessee - Knoxville
Novel Bimetallic Plasmonic Nanomaterials, Ritesh Sachan
Doctoral Dissertations
Plasmonic nanomaterials have attracted a lot of attention recently due to their application in various fields such as chemical and biological sensing, catalysis, energy harvesting and optical devices. However, there is a need to address several outstanding issues with these materials, including cost-effective synthesis, tunability in plasmonic characteristics, and long term stability. In this thesis, we have focused on bimetallic nanoparticles (NPs) of Ag and Co due to their immiscibility as well as their individual properties. First, a pulsed laser induced dewetting route was used to synthesize Ag-Co bimetallic plasmonic NPs. An synthesis parameter space was derived to show the …
New Application For Indium Gallium Zinc Oxide Thin Film Transistors: A Fully Integrated Active Matrix Electrowetting Microfluidic Platform, 2013 University of Tennessee, Knoxville
New Application For Indium Gallium Zinc Oxide Thin Film Transistors: A Fully Integrated Active Matrix Electrowetting Microfluidic Platform, Jiyong Noh
Doctoral Dissertations
The characterization and fabrication of active matrix TFTs [Thin Film Transistors] have been studied for applying an addressable microfluidic electrowetting channel device. The a-IGZO [Amorphous Indium Gallium Zinc Oxide] is used for electronic switching device to control the microfluidic device because of its high mobility, transparency, and easy to fabrication. The purpose of this dissertation is to optimize each IGZO TFT process including the optimization of a-IGZO properties to achieve robust device for application. To drive the IGZO TFTs, the channel resistance of IGZO layer and contact resistance between IGZO layer and source/drain (S/D) electrode are discussed in this dissertation. …
Strategic Electronic Property Control Of Self-Assembling Pyrazine-Acenes, 2013 University of Nevada, Las Vegas
Strategic Electronic Property Control Of Self-Assembling Pyrazine-Acenes, Lacie Brownell
UNLV Theses, Dissertations, Professional Papers, and Capstones
Control of electronic properties in organic semiconductor materials is essential for electro-optical applications such as field-effect transistors, light-emitting diodes, and photovoltaic devices. This work is focused on two systems that highlight different approaches for the manipulation of electronic properties: (I) the development of electron-deficient (n-type) materials by selective lowering of ELUMO and (II) low energy gap materials by controlling both ELUMO and EHOMO
To specifically lower ELUMO, a pyrazine-acene π-platform was extended using electron-withdrawing moieties. These include: pyridine, pyrazine, and benzothiadiazole (system I). From the base pyrazine-acene, the most significant change in ELUMO of …
Fabrication And Characterization Of Si(1-X)Ge(X) Semiconductor Alloy For Sensor Applications, 2013 University of Tennessee - Knoxville
Fabrication And Characterization Of Si(1-X)Ge(X) Semiconductor Alloy For Sensor Applications, Daniel Aaron Schaeffer
Masters Theses
Si1-xGex [Si(1-x)Ge(x)] semiconductor alloys have emerged as materials with many important applications in the electronic industry due to its tunable electronic, optical, and physical properties. It has been studied and analyzed for the fabrication of high-speed micro electronics (e.g., SiGe heterojunction bipolar transistors (HBT) and high electron mobility field effect transistors) and thermo-photovoltaics (e.g., photodetectors, solar cells, thermoelectric power generators and temperature sensors). Other applications of Si1-xGex include tunable neutron and x-ray monochromators and γ- ray [gamma-ray] detectors. In these applications, the Si1-xGex alloy is generally used in the form of …
Iii-V Bismide Optoelectronic Devices, 2013 University of Arkansas, Fayetteville
Iii-V Bismide Optoelectronic Devices, Dongsheng Fan
Graduate Theses and Dissertations
This dissertation explores modeling, molecular beam epitaxy growth, and fabrication of III-V bismide optoelectronic devices, which are of great importance in modern applications of telecommunication, gas sensing, environment monitoring, etc. In the current room-temperature continuous-wave operational GaSb-based type-I InGaAsSb/AlGaInAsSb quantum well laser diodes in 3-4 um mid-wavelength range, the lasing wavelength and performance of the devices are limited due to the lack of hole confinement in the active regions. In this dissertation, a novel GaSb-based GaInAsSbBi material is proposed to replace the conventional InGaAsSb material in the quantum well region, which enables the laser diodes achieve up to 4 µm …
Device Characterization And Compact Modeling Of The Sige Hbt In Extreme Temperature Environments, 2013 University of Arkansas, Fayetteville
Device Characterization And Compact Modeling Of The Sige Hbt In Extreme Temperature Environments, Beth Olivia Woods
Graduate Theses and Dissertations
The silicon germanium heterojunction bipolar transistor, SiGe HBT, has very high frequency response but limited voltage range. Commercial communication applications in wireless and system integration have driven the development of the SiGe HBT. However, the device's excellent electrical performance goes beyond the commercial environment. The SiGe HBT performs exceptionally at low temperatures. The device DC current gain and AC small-signal gain significantly increase in the cryogenic temperature range. Applications at low temperatures with expansive temperature range specifications need an HBT compact model to accurately represent the device's performance.
In this work, a compact model referenced at 300K was developed to …