Nylon-6 Fabric Nanocomposite Resistance Temperature Detectors - Effects Of Oxidant, Mwcnt, And Nylon-6 Concentration, Rebecca Howdyshell

Williams Honors College, Honors Research Projects

Abstract

The purpose of this honors project is to construct and test temperature detectors, which can be used for the advancement of exercise devices, prosthetic sockets, or medical applications. Resistance Temperature Detectors (RTDs) are an effective way to measure temperature due to the dependence of the RTD material’s resistance on temperature. The focus of this project was to develop an RTD for prosthetic socket or exercise applications, where the RTD is in close contact with the skin of the user. Generally, RTDs are constructed from platinum, copper, or nickel. However, metal RTDs have a tendency to be large and rigid, …

Influence Of Resonant And Non-Resonant Vibrational Excitation Of Ammonia Molecules In Gallium Nitride Synthesis, Hossein Rabiee Golgir, Yunshen Zhou, Kamran Keramatnejad, Yongfeng Lu

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Attempts on the selective promotion of gallium nitride (GaN) growth were investigated by deploying laserassisted vibrational excitation of reactant molecules, which deposits energy selectively into specific molecules and activate the molecules towards the selected reaction pathways. Laser-assisted metal organic chemical vapor deposition (LMOCVD) of GaN was studied using a wavelength-tunable CO2 laser. The NH-wagging modes (υ2) of ammonia (NH3) precursor molecules are strongly infrared active and perfectly match the emission line of the CO2 laser at 9.219, 10.350, and 10.719 μm. On- and off-resonance excitations of molecules were performed via tuning the incident laser wavelengths at on-resonant wavelength 9.219 μm …

Monolithic Optofluidic Ring Resonator Lasers Created By Femtosecond Laser Nanofabrication, Hengky Chandrahalim, Qiushu Chen, Ali A. Said, Mark Dugan, Xudong Fan

Faculty Publications

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ/mm². Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10⁴, which is limited by both solvent …

Tunable Optical Nanocavity Of Iron-Garnet With A Buried Metal Layer, Alexey N. Kuz'michev, Lars E. Kreilkamp, Mohammed Nur-E-Alam, Evgeni Bezus, Mikhail Vasilev, Iliya A. Akimov, Kamal Alameh, Manfred Bayer, Vladimir I. Belotelov

Research outputs 2014 to 2021

We report on the fabrication and characterization of a novel magnetophotonic structure designed as iron garnet based magneto-optical nanoresonator cavity constrained by two noble metal mirrors. Since the iron garnet layer requires annealing at high temperatures, the fabrication process can be rather challenging. Special approaches for the protection of metal layers against oxidation and morphological changes along with a special plasma-assisted polishing of the iron garnet layer surface were used to achieve a 10-fold enhancement of the Faraday rotation angle (up to 10.8°=μm) within a special resonance peak of 12 nm (FWHM) linewidth at a wavelength of 772 nm, in …

Sulfur Vacancies In Photorefractive Sn2P2S6 Crystals, Eric M. Golden, Sergey A. Basun, A. A. Grabar, I. M. Stoika, Nancy C. Giles, D. R. Evans, Larry E. Halliburton

Faculty Publications

A photoinduced electron paramagnetic resonance (EPR) spectrum in single crystals of Sn2P2S6 (SPS) is assigned to an electron trapped at a sulfur vacancy. These vacancies are unintentionally present in undoped SPS crystals and are expected to play an important role in the photorefractive behavior of the material. Nonparamagnetic sulfur vacancies are formed during the initial growth of the crystal. Subsequent illumination below 100 K with 442 nm laser light easily converts these vacancies to EPR-active defects. The resulting S = 1/2 spectrum shows well-resolved and nearly isotropic hyperfine interactions with two P ions and two Sn ions. Partially resolved interactions …

Solution Processed Cu(In,Ga)S2 Thin Film And Nanowire Photovoltaics, Johnthan Armstrong

Theses and Dissertations

Solar energy conversion is a highly attractive process for clean and renewable power for the future. Cu(In,Ga)(Se,S)2/CdS/ZnO has proven itself to be a worthwhile photovoltaic combination achieving record efficiencies upwards of 20%. These record efficiencies have been obtained through vacuum-based approaches. However, the high cost of vacuum-based fabrication processes become a barrier to affordable solar cells as an energy source. As a result, solution-based approaches have become the focus of many studies which have achieved record efficiencies of 15%. These solution-based approaches have not matched up with the vacuum-based approaches. In this work, we investigate methods to improve the solution-based …

Performance Analysis Of A Hybrid Raman Optical Parametric Amplifier In The O- And E-Bands For Cwdm Pons, Sasanthi Peiris, Nicolas Madamopoulos, Neophytos A. Antoniades, Dwight Richards, Roger Dorsinville

Publications and Research

We describe a hybrid Raman-optical parametric amplifier (HROPA) operating at the O- and E-bands and designed for coarse wavelength division multiplexed (CWDM) passive optical networks (PONs). We present the mathematical model and simulation results for the optimization of this HROPA design. Our analysis shows that separating the two amplification processes allows for optimization of each one separately, e.g., proper selection of pump optical powers and wavelengths to achieve maximum gain bandwidth and low gain ripple. Furthermore, we show that the proper design of optical filters incorporated in the HROPA architecture can suppress idlers generated during the OPA process, as well …

Highly Transparent, Self-Cleaning, And Antireflective Nanoparticle Coatings, Corey Seth Thompson

Graduate Theses and Dissertations

Current solar panel technologies require a sheet of glass to serve as both mechanical support and to protect the cells from the environment. The reflection from the glass sheet can reflect up to 8% of the incident light, reducing the power output of the panel. Antireflective coatings can be used to allow more light to enter the panel to be converted into usable electricity. However, no solid thin film materials exhibit a low enough index of refraction to serve as antireflective coatings for common solar glass. The main goal of this research was to investigate the self-cleaning, antifogging, and antireflective …

Gesn Light-Emitting Devices, Yiyin Zhou

Graduate Theses and Dissertations

Silicon based optoelectronic devices have been investigated for decades. However, due to the indirect band gap nature of Si and Ge, developing of efficient light-emitting source on Si is still a challenging topic. GeSn based optoelectronic devices have the great potential to overcome this deficiency for several reasons. By adding more fraction of Sn into Ge, GeSn band gap could be reduced. The narrowed band gap could be developed for near to mid infrared applications. The alloy can even become the direct band gap material with a large Sn composition (beyond 8%). This feature could enhance the light emission from …

Development Of A High Precision Quantum Dot Synthesis Method Utilizing A Microfluidic Reactor And In-Line Fluorescence Flow Cell, William Henry Lafferty

Master's Theses

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 quality, size, and fluorescence of quantum dots depend on parameters that are difficult to control using traditional batch synthesis processes. An alternative, high precision process was developed for the synthesis of cadmium-selenide quantum dots using a microfluidic reactor and fluorescence flow cell. The process required creating separate cadmium and selenium precursors that were then mixed in a nitrogen environment at 17°C. Using an NE-300^® syringe pump, the solution …

Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy, Wen-Hua Leng

Journal of Electrochemistry

Semiconductor photoelectrochemical hydrogen production is an important and promising technology for utilizing solar energy. The efficiency of hydrogen production depends on the efficiencies of separation and transport of photo-generated carriers. A deep understanding of the behavior of these processes has guiding significance for designing efficient solar hydrogen device. photoelectrochemical and transient absorption spectroscopy methods are powerful tool for studying the microscopic dynamics and mechanism of photocatalytic reaction. This review describes the part of the latest results of the author regarding the semiconductor photoelectrochemical hydrogen production obtained by these methods,and the problems and future research priorities in this field are proposed.

Effects Of Thermal Boundary Conditions During Finite Element Modeling Of Physical Vapor Transport, Wade Luhman

Journal of Undergraduate Research at Minnesota State University, Mankato

Physical vapor transport (PVT) is a material processing method commonly used to produce different types of semiconductor materials. Computer modeling of PVT is important to understand the fundamentals of the processing method. Due to the large amount of computer processing power and storage needed to solve the computer models many of the previously solved simulations have been simplified to efficiently utilize computer usage. Previous PVT computer simulations of mercurous chloride (Hg2Cl2) have assumed constant temperature profiles on the source and crystal substrate for simplicity. These simulations were performed using the FIDAP computational fluid dynamics software package. In this research the …

Single Cuo Nanowires Electrical Properties And Application On Photoelectrochemical Water Splitting, Junnan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Charge transport in single crystal, p type copper oxide (CuO) nanowires (NWs) was studied through temperature based (120 K – 400 K) current-voltage (I-V) measurements of 2-terminal single NW devices. Individual CuO NWs with an average diameter of 220 nm were attached to Au electrodes 2.5 µm apart, using a dielectrophoresis method. I-V curves showed a transition from linear behavior at low bias to strong power law dependence (I ~ V^a) at high bias, which can be attributed to space charge limited current (SCLC) mechanism. At low electrical fields (< 0.89 × 10³ V·cm^-1), the number of …

Three Dimensional Transient Asymmetric Flowfields In Physical Vapor Transport, Joseph Dobmeier

Journal of Undergraduate Research at Minnesota State University, Mankato

Physical Vapor Transport is a manufacturing process used to produce single crystals of semiconductor materials such as mercurous chloride (Hg2Cl2). In the past this time-varying process has been studied with numerical simulation by considering three dimensional flow using an axi-symmetric two dimensional model or by restricting the simulation to asymmetric two dimensional flow and dropping the assumption of axi-symmetry from the model. It is generally agreed that neither of these methods accurately represent the true behavior of the process. The purpose of this research was to extend the asymmetric two dimensional model to three dimensions thereby obtaining a solution which …

Polymer-Based Thermoelectric Devices, Stuart W. Hilsmier, Edward P. Tomlinson, Bryan Boudouris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, over 50% of all energy generated in the US is lost as waste heat, and thermoelectric generators offer a promising means to recoup some of this energy, if their efficiency is improved. While organic thermoelectric materials lack the efficiency of their inorganic counterparts, they are composed of highly abundant resources and have low temperature processing conditions. Recently, a new class of redox-active polymers, radical polymers, has exhibited high electrical conductivity in an entirely amorphous medium. In addition, these radical polymers have a simple synthetic scheme and can be highly tunable to provide desired electrical properties. In this study, the …

Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …

Micro-Mechanics Simulation Tool Optimization, Ruixuan Ren, Marisol Koslowski

The Summer Undergraduate Research Fellowship (SURF) Symposium

Crystalline films grown epitaxially on substrates consisting of a different crystalline material are of considerable interest in optoelectronic devices and the semiconductor industry. One way to progress in this field is to develop simulation tools based on specially designed numerical method. A nanoHUB simulation tool was developed based on the phase field theory, which considers the propagation of dislocations inside the crystalline film. However, the current tool needs several improvements to be more realistic and user-friendly. First, the inputs of the simulation tool are adjusted so that the user can use this tool directly without any additional calculation. The output …

Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thin film solar cells have higher absorption coefficients than traditional Silicon solar cells. This means that lesser material is required to produce the same power output for a given intensity of solar illumination. As a result, they are less expensive, easier to install and have a wider range of applications. Analyzing the performance of cells requires separating the current into the photocurrent and the injection current based on the ‘Superposition Principle’. For thin film solar cells, this cannot be done using the conventional method. This is because these components are interdependent, and so modeling one’s behavior requires understanding the other. …

Development Of A Silicon Nanowire Mask Using Scanning Probe Microscopy, Ross Gregoriev

Master's Theses

Scanning probe microscopy techniques were used to investigate the desorption of hydrogen passivated silicon to form SiO2 etch masks The application of the etch masks were planned on being used to manufacture silicon nanowires. Low concentration hydrofluoric acid was used to passivate the surface. The surface was selectively depassivated by SPM techniques. Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) were used to create the masks. The STM system used was found to desorb hydrogen from the surface faster than the STM could image and was considered incapable in the configuration investigated. This led to the use of atomic …

Effects Of Nanoholes Grown By Molecular Beam Droplet Epitaxy On Electrical Properties Of Two Dimensional Electron Gas, Yusuke Hirono

Graduate Theses and Dissertations

The effects of nanoholes, grown by molecular beam droplet epitaxy, on the electrical properties of quantum well (QW) heterostructures are reported. To investigate how the depth of nanoholes affect the electrical properties of the QW heterostructures, the growth conditions for nanoholes were optimized with respect to their depth and density. Using the results of the optimization of the nanohole growth, three InGaAs pseudomorphic quantum wells with nanoholes were investigated with varied depth and a constant density. A QW heterostructure without nanoholes was grown as a reference structure. For all the samples, temperature dependent Hall effect measurements, noise studies as a …