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Reactive Ion Etching Selectivity Of Si/Sio2: Comparing Of Two fluorocarbon Gases Chf3 And Cf4, Meiyue Zhang, Pat Watson 2019 Singh Center for Nanotechnology

Reactive Ion Etching Selectivity Of Si/Sio2: Comparing Of Two fluorocarbon Gases Chf3 And Cf4, Meiyue Zhang, Pat Watson

Protocols and Reports

Two reactive ion etching (RIE) processes were studied to show the relative etch selectivity between SiO2 and Si using two fluorocarbon gases, CF4 and CHF3. Results show that CHF3 gives better selectivity (16:1) over CF4 (1.2 :1). On the other hand, the etch rate of SiO2 of CF4 is approximately 52.8 nm/min, faster than CHF3 (32.4 nm/min).


A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak 2019 Purdue University

A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak

Faculty Publications

The realization of Internet of Underground Things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1-0.4m), change in soil ...


Investigating The Role Of Coil Designs And Anatomical Variations In Cerebellar Tms, Xiaojing Zhong, Priyam Rastogi, Yifei Wang, Erik G. Lee, David C. Jiles 2019 Iowa State University

Investigating The Role Of Coil Designs And Anatomical Variations In Cerebellar Tms, Xiaojing Zhong, Priyam Rastogi, Yifei Wang, Erik G. Lee, David C. Jiles

Electrical and Computer Engineering Publications

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique that is used for treating various neurological disorders such as major depressive disorder. TMS has been gaining popularity in the field of neurostimulation of the cerebellum, since the cerebellum is a complex structure connected with almost the entire central nervous system and TMS has promise for non-invasively probing cerebellar function. Recent studies have discovered that the cerebellum plays an important role not only in motor planning and behavior but also in the cognitive domain. However, few studies have explored how different coil designs and anatomical variations affect the effectiveness of cerebellar ...


Optical Micro-Seismometer Based On Evanescent Field Perturbation Of Whispering Gallery Modes, Jaime Da Silva 2018 Southern Methodist University

Optical Micro-Seismometer Based On Evanescent Field Perturbation Of Whispering Gallery Modes, Jaime Da Silva

Mechanical Engineering Research Theses and Dissertations

This thesis proposes a light-weight, compact, and accurate optical micro-seismometer that could be used in many applications, such as planetary exploration. The sensor proposed here is based on the principle of whispering gallery optical mode (WGM) resonance shifts of a dielectric micro-resonator due to disturbances of its evanescent field. The micro-seismometer could be used in place of the traditional bulky seismometers. The design of a waveguide-resonator and mechanical structure to disturb the evanescent field are presented. A proof-of-concept a seismometer model that uses a 5µm ring resonator is numerically tested with actual seismic data. The results show that a WGM-based ...


Growth And Behaviors Of Inn/Gan Multiple Quantum Wells By Plasma-Assisted Molecular Beam Epitaxy, Chen Li 2018 University of Arkansas, Fayetteville

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

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 ...


Growth And Characterization Of Silicon-Germanium-Tin Semiconductors For Future Nanophotonics Devices, Bader Saad Alharthi 2018 University of Arkansas, Fayetteville

Growth And Characterization Of Silicon-Germanium-Tin Semiconductors For Future Nanophotonics Devices, Bader Saad Alharthi

Theses and Dissertations

The bright future of silicon (Si) photonics has attracted research interest worldwide. The ultimate goal of this growing field is to develop a group IV based Si foundries that integrate Si-photonics with the current complementary metal–oxide–semiconductor (CMOS) on a single chip for mid-infrared optoelectronics and high speed devices. Even though group IV was used in light detection, such as photoconductors, it is still cannot compete with III-V semiconductors for light generation. This is because most of the group IV elements, such as Si and germanium (Ge), are indirect bandgap materials. Nevertheless, Ge and Si attracted industry attention because ...


Transcribing Braille Code: Learning Equations Across Platforms, Deegan Atha, Courtney Balogh 2018 Purdue University

Transcribing Braille Code: Learning Equations Across Platforms, Deegan Atha, Courtney Balogh

Purdue Journal of Service-Learning and International Engagement

Deegan Atha, a graduating senior in electrical engineering and a future engineer, is interested in human-centered design and developing technology that helps students engage and be successful in STEM.

Courtney Balogh, a junior in mechanical engineering, is interested in human-centered design and the importance it plays in product development. Deegan and Courtney are members of the Purdue EPICS project, Learning Equations Across Platforms (LEAP). They partnered with the Indiana School for the Blind and Visually Impaired (ISBVI) to develop a braille transcription device and web application that converts braille to print in real time.


Genetic Algorithm Design Of Photonic Crystals For Energy-Efficient Ultrafast Laser Transmitters, Troy A. Hutchins-Delgado 2018 University of New Mexico

Genetic Algorithm Design Of Photonic Crystals For Energy-Efficient Ultrafast Laser Transmitters, Troy A. Hutchins-Delgado

Shared Knowledge Conference

Photonic crystals allow light to be controlled and manipulated such that novel photonic devices can be created. We are interested in using photonic crystals to increase the energy efficiency of our semiconductor whistle-geometry ring lasers. A photonic crystal will enable us to reduce the ring size, while maintaining confinement, thereby reducing its operating power. Photonic crystals can also exhibit slow light that will increase the interaction with the material. This will increase the gain, and therefore, lower the threshold for lasing to occur. Designing a photonic crystal for a particular application can be a challenge due to its number of ...


Study Of Physical Layer Security And Teaching Methods In Wireless Communications, Zhijian Xie, Christopher Horne 2018 NC A&T State Unversity

Study Of Physical Layer Security And Teaching Methods In Wireless Communications, Zhijian Xie, Christopher Horne

KSU Proceedings on Cybersecurity Education, Research and Practice

In most wireless channels, the signals propagate in all directions. For the communication between Alice and Bob, an Eavesdropper can receive the signals from both Alice and Bob as far as the Eavesdropper is in the range determined by the transmitting power. Through phased array antenna with beam tracking circuits or cooperative iteration, the signals are confined near the straight line connecting the positions of Alice and Bob, so it will largely reduce the valid placement of an Eavesdropper. Sometimes, this reduction can be prohibitive for Eavesdropper to wiretap the channel since the reduced space can be readily protected. Two ...


Tailoring The Asymmetric Magnetoimpedance Response In Exchange-Biased Ni - Fe Multilayers, Ufuk Kilic, Carolina Ross, Carlos Garcia 2018 University of Nebraska - Lincoln

Tailoring The Asymmetric Magnetoimpedance Response In Exchange-Biased Ni - Fe Multilayers, Ufuk Kilic, Carolina Ross, Carlos Garcia

Ufuk Kilic

The dependence of the asymmetric magnetoimpedance (MI) response on the directions of both the magnetic field and the exchange bias is studied for an [NiFe(60nm)/IrMn(35nm)]×5 multilayer system. The antiferromagnetic (AFM) layers create an exchange bias that shifts both the hysteresis loop and the MI response of NiFe; the strength of this coupling depends on the thicknesses of both the ferromagnetic layer and the AFM layer. Tuning the exchange-bias angle and the applied-magnetic-field direction provides a practical method to control the symmetry and the magnitude of the MI response. The observed asymmetric response can ...


Instrumentation For Cryogenic Dynamic Nuclear Polarization And Electron Decoupling In Rotating Solids, Faith Joellen Scott 2018 Washington University in St. Louis

Instrumentation For Cryogenic Dynamic Nuclear Polarization And Electron Decoupling In Rotating Solids, Faith Joellen Scott

Arts & Sciences Electronic Theses and Dissertations

Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) using the higher polarization of electron radical spins compared to nuclear spins. The addition of electron radicals for DNP to the sample can cause hyperfine broadening, which decreases the resolution of the NMR resonances due to hyperfine interactions between electron and nuclear spins. Electron decoupling has been shown to attenuate the effects of hyperfine coupling in rotating solids. Magic angle spinning (MAS) DNP with electron decoupling requires a high electron Rabi frequency provided by a high-power microwave source such as a frequency-agile gyrotron. This dissertation describes the development ...


Indirect Imaging Using Heterodyne Remote Digital Holography, Muralidhar Madabhushi Balaji 2018 Southern Methodist University

Indirect Imaging Using Heterodyne Remote Digital Holography, Muralidhar Madabhushi Balaji

Electrical Engineering Theses and Dissertations

Conventional line-of-sight imaging techniques rely on detecting light paths bouncing from the object and reaching directly to the detector. Absence of any such direct light paths from object to detector results in a failure to recover any useful information using conventional techniques. The absence of direct light paths from object to detector can be observed in several real-world scenarios such as looking around a corner, imaging through turbid media, imaging through tissue etc.

The focus of this thesis is pertaining to the problem of looking around corners (or) imaging object hidden from line of sight at macroscopic scales. This thesis ...


A High-Efficiency Low Power Rectifier For Wireless Power Transfer, Zachary Loy, Alden Fisher, Brian Vaughn, Dimitrios Peroulis 2018 Purdue University

A High-Efficiency Low Power Rectifier For Wireless Power Transfer, Zachary Loy, Alden Fisher, Brian Vaughn, Dimitrios Peroulis

The Summer Undergraduate Research Fellowship (SURF) Symposium

With the number of implantable devices that utilize electronics increasing, there is an increasing need to find alternative ways of powering them. Currently, surgery is required to replace a battery for these devices; however, with advancements in Wireless Power Transfer (WPT) methods, the need for further surgeries will become negated. This paper explores the ability of WPT as an alternative powering method by investigating rectifier Power Conversion Efficiency (PCE). The rectifier converts high frequency waves to Direct Current (DC) energy that can provide usable power to devices requiring electrical power. It is targeted for low power applications centered around a ...


Spice Based Compact Model For Electrical Switching Of Antiferromagnet, Xe Jin Chan, Jan Kaiser, Pramey Upadhyaya 2018 Purdue University

Spice Based Compact Model For Electrical Switching Of Antiferromagnet, Xe Jin Chan, Jan Kaiser, Pramey Upadhyaya

The Summer Undergraduate Research Fellowship (SURF) Symposium

A simulation framework that can model the behavior of antiferromagnets (AFMs) is essential to building novel high-speed devices. The electrical switching of AFMs allows for high performance memory applications. With new phenomena in spintronics being discovered, there is a need for flexible and expandable models. With that in mind, we developed a model for AFMs which can be used to simulate AFM switching behavior in SPICE. This approach can be modified for adding modules, keeping pace with new developments. The proposed AFM switching model is based on the Landau-Lifshitz-Gilbert equation (LLG). LLG along with an exchange coupling module is implemented ...


Experimental Evaluation Of A Krypton Propellant Arrangement In A T-100-3 Hall-Effect Thruster, Adam Patel, Javier Cortina Fernandez, Justin Chow, Osvaldo Alejandro Martin, Alexey Shashurin 2018 Purdue University

Experimental Evaluation Of A Krypton Propellant Arrangement In A T-100-3 Hall-Effect Thruster, Adam Patel, Javier Cortina Fernandez, Justin Chow, Osvaldo Alejandro Martin, Alexey Shashurin

The Summer Undergraduate Research Fellowship (SURF) Symposium

Stationary Hall thrusters are electric, moderate-specific impulse propulsion systems developed in Russia. These devices manipulate electric and magnetic fields to expel ionized gas (plasma) components, resulting in thrust. The success of Hall-effect engines in USSR satellite-transfer missions quickly sparked western interest in the design. Extensive government and academic study commenced shortly after the dissolution of the Soviet Union, when the technology was made available to the United States. The common SPT-100 model was the primary subject of such studies. Unfortunately, limited literature exists for rare and uncommon Hall thruster models. The T-100-3 stationary plasma thruster suffers from this gap; few ...


Remote Sensing Using I-Band And S-Band Signals Of Opportunity, Kadir Efecik, Benjamin R. Nold, James L. Garrison 2018 Purdue University

Remote Sensing Using I-Band And S-Band Signals Of Opportunity, Kadir Efecik, Benjamin R. Nold, James L. Garrison

The Summer Undergraduate Research Fellowship (SURF) Symposium

Measurement of soil moisture, especially the root zone soil moisture, is important in agriculture, meteorology, and hydrology. Root zone soil moisture is concerned with the first meter down the soil. Active and passive remote sensing methods used today utilizing L-band(1-2GHz) are physically limited to a sensing depth of about 5 cm or less. To remotely sense the soil moisture in the deeper parts of the soil, the frequency should be lowered. Lower frequencies cannot be used in active spaceborne instruments because of their need for larger antennas, radio frequency interference (RFI), and frequency spectrum allocations. Ground-based passive remote sensing ...


Inverse Design Of Three-Dimensional Frequency Selective Structures And Metamaterials Using Multi-Objective Lazy Ant Colony Optimization, Danny Zhu 2018 United States Military Academy

Inverse Design Of Three-Dimensional Frequency Selective Structures And Metamaterials Using Multi-Objective Lazy Ant Colony Optimization, Danny Zhu

West Point ETD

With the rise of big data and the “internet of things,” wireless signals permeate today’s environment more than ever before. As the demand for information and security continues to expand, the need for filtering a crowded signal space will become increasingly important. Although existing devices can achieve this with additional components, such as in-line filters and low noise amplifiers, these approaches introduce additional bulk, cost and complexity. An alternative, low-cost solution to filtering these signals can be achieved through the use of Frequency Selective Surfaces (FSSs), which are commonly used in antennas, polarizers, radomes, and intelligent architecture. FSSs typically ...


Imaging Characterization Of Current Generating Lipid-Protein Membranes, Joel D. Kamwa 2018 University of Arkansas, Fayetteville

Imaging Characterization Of Current Generating Lipid-Protein Membranes, Joel D. Kamwa

Graduate School Student Works

Imaging Characterization of Current Generating Lipid-protein Membranes


High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen 2018 University of Louisville

High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen

Electronic Theses and Dissertations

Much of what we know about fundamental physical law and the universe derives from observations and measurements using optical methods. The passive use of the electromagnetic spectrum can be the best way of studying physical phenomenon in general with minimal disturbance of the system in the process. While for many applications ambient visible light is sufficient, light outside of the visible range may convey more information. The signals of interest are also often a small fraction of the background, and their changes occur on time scales so quickly that they are visually imperceptible. This thesis reports techniques and technologies developed ...


Hybrid Perovskite Characterization And Device Applications., Kasun Fernando 2018 University of Louisville

Hybrid Perovskite Characterization And Device Applications., Kasun Fernando

Electronic Theses and Dissertations

Hybrid perovskites are a group of materials that has shown a great impact in the field of scientific research in the past decade due to the efficiency gain within a short period of time. Hot casting is one technique that has been producing high efficient and stable solar cells. Electrical transportation of lateral device structure by such film is explored to understand basic properties and predict possible device applications using it. Under dark, memristive ability of the film was explored using various experiments. Unique uni-polar memristor ability was observed. Using the experimental results, a model is hypothesized using the concepts ...


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