Semiconductor and Optical Materials Commons^™

A Fault-Tolerant Exchange-Coupled Spin-Ensemble Qubit At Elevated-Temperatures, Aniruddha Chakraborty

Theses and Dissertations

This thesis introduces a novel qubit architecture: the ferromagnetic exchange-coupled spin ensemble qubit (E-qubit), designed to address the noise-induced instability. In this work, the time evolution of the ensemble’s density matrix is studied using the Liouville–von Neumann equation. To benchmark against a single-spin qubit, the gate fidelity of an E-qubit is computed in the presence of thermal noise. Coherence time is also analyzed under identical thermal condition and a linear scaling is observed with qubit size . The results show that, at 6 K , the gate fidelity error (0.7 % ) of the seven- spin ensemble is an order …

Development Of Group Iii-V Quantum Confinement-Enabled Detectors: Bias-Tunable Quantum Well Infrared Photodetector (Qwip) And Quantum Dot Scintillation Detector (Qdsd), Gyana R. Biswal

Electronic Theses & Dissertations (2024 - present)

This dissertation discloses the physics, fabrication, characterization, and analysis of two novel types of group III-V semiconductor detectors relying on quantum confinement of carriers, namely voltage-tunable quantum well infrared photodetectors (QWIP) and a high-yield ultrafast quantum dot scintillation detector (QDSD). Both QWIP and QDSD heterostructures presented here were grown on 3” GaAs (001) substrates using molecular beam epitaxy (MBE).

A major part of the dissertation focuses on development of the voltage-tunable QWIPs targeting detection in the mid-wave infrared region (MWIR) (3μm -5μm) and long-wave infrared region (LWIR) (8μm -12μm) with control of sensitivity by the applied bias. The QWIPs utilize …

Investigating The Roles Of Intrinsic Point Defects And Transition Metal Doping In Monolayer And Bulk Tis2, Patrick J. Keeney

UNF Graduate Theses and Dissertations

Within this thesis, the magnetic and electronic properties of various 1T-TiS₂ systems are thoroughly examined using density functional theory (DFT) and scanning tunneling microscopy (STM). Formation energies and electronic implications of intrinsic point defects in bulk TiS₂ and monolayer TiS₂ are analyzed by approximating a computational monolayer of TiS₂ as the surface layer of a bulk sample. This approximation is validated given that intralayer covalent bonding dominates interlayer van der Waals interactions. We conclude that the most energetically favorable intrinsic defects are Ti atoms settling above the outermost S plane and S vacancies. In addition, the …

Contributions To Journal Of Electrochemistry, The Flagship Journal Of Chinese Chemical Society Electrochemical Committee, Will Be Listed As A New Recommendation Policy For China Youth Awards Of Electrochemist, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Ge/Sige Quantum Wells: Material For The Post-Moore Era, Troy Alexander Hutchins-Delgado

Optical Science and Engineering ETDs

This dissertation demonstrates high-quality germanium quantum wells on a 200 mm silicon wafer platform, enabling novel device possibilities. Partnering with a commercial silicon-germanium epitaxy supplier, we obtained shallow, undoped germanium quantum wells with high-crystalline quality, confirmed through x-ray diffraction, secondary ion mass spectroscopy, high-resolution scanning transmission electron microscopy, and energy dispersive x-ray spectroscopy. Hall bar devices fabricated on single quantum wells revealed that surface preparation can tune transport properties while maintaining peak mobilities around 10⁵ cm²V⁻¹s⁻¹. Manganese-germanide spintronic contacts were integrated via solid-state reaction, with contact quality assessed through Schottky diodes, transfer length …

Understanding Defect Dynamics In Black Phosphorene Under Noble Gas Ion Irradiation., Saransh Gupta

Electronic Theses and Dissertations

Controlled introduction of defects in phosphorene using high-energy ion beams offers a promising route to design novel high-performance materials for energy technologies. However, this potential remains underexplored due to a lack of fundamental understanding of the atomic-scale mechanisms governing the production, accumulation, and temporal evolution of defects during ion irradiation. Here, we employ a combination of classical and ab initio molecular dynamics simulations to elucidate the effects of ion energy, angle of incidence, noble gas ion size/mass, and fluence on (a) defect generation (i.e., point defects, topological imperfections, voids), (b) atomic-scale mechanisms of defect formation and re-arrangement, and (c) defect …

Journal Of Electrochemistry, The Flagship Journal Of Chinese Chemical Society Electrochemical Committee, Made A Public Appearance At The 22nd National Electrochemical Congress, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

The Award Ceremony Of The 2nd Xiamen University Short Video Abstract Contest For Science And Technology Journal Papers Came To A Successful Conclusion, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Goodbye With Tears! Deep Condolences To Academician Zhao-Wu Tian!, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

The Adviser Of Journal Of Electrochemistry Professor Christian Amatore Received The Chinese Government Friendship Award, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Journal Of Electrochemistry Is Selected To Entering Ici Journals Master List, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Zhong-Qun Tian, Academician And Honorary Member Of Electrochemistry Committee Chinese Chemical Society, Achieved "Raman Lifetime Award", Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Chinese Chemical Society: First Young Scholars' Symposium On Electrosynthesis Held Successfully, Chinese Society Of Electrochemistry (Cse)

Journal of Electrochemistry

No abstract provided.

2024 Tianmulake Advanced Anode Materials Innovation Forum And Sixth National Conference Of Advanced Battery Failure Analysis And Testing Technology Concluded Successfully, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Winning Results Of The 2Nd Xiamen University Short Video Abstract Contest For Science And Technology Papers, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

2024 World Fuel Cell Conference Held In Ningbo, Zhejiang, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Rate Law For Photoelectrochemical Water Splitting Over Cuo, Bo-Yuan Gao, Wen-Hua Leng

Journal of Electrochemistry

Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen. However, the determination of rate law is rarely reported. To this purpose, copper oxide (CuO) is selected as a model photocathode in this study, and the photogenerated surface charge density, interfacial charge transfer rate constant and their relation to the water reduction rate (in terms of photocurrent) were investigated by a combination of (photo)electrochemical techniques. The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density, and that the photocurrent equals to the product of the charge transfer rate constant …

Winning Works From Journal Of Electrochemistry: The 2Nd Xiamen University Short Video Abstract Contest For Science And Technology Journal Papers, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

2024 "Electrochemical Research Paradigms" Summer School Successfully Held, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Upcoming Meeting-The 1St Young Investigator Symposium On Electrosynthesis, Chinese Chemical Society, Chinese Society Of Electrochemistry (Cse)

Journal of Electrochemistry

No abstract provided.

Secondary Electron Yield Of Metals, Alloys, And Metal Oxides From First Principles Based Monte Carlo Simulations, Raul E. Gutierrez

Electrical and Computer Engineering ETDs

Density Functional Theory (DFT) based Monte Carlo (MC) simulations of the Sec-
ondary Electron Yield (SEY) of metals, alloys, and metal oxides are performed to
find material properties that could help reduce or influence the multipactor effect.
In order to accurately model the SEY of materials, knowledge of the frequency- and
momentum-dependent Energy Loss Function (qDepELF) is required. The qDepELF
is difficult to determine from experiment; however, it can be calculated from first
principles. The DFT-MC approach for simulating the secondary electron genera-
tion, propagation, and emission processes is described herein. Material properties,
which are calculated using DFT and used …

First Announcement Of 76th Annual Meeting Of The International Society Of Electrochemistry, International Society Of Electrochemistry (Ise)

Journal of Electrochemistry

No abstract provided.

In Situ Diffuse Reflectance Spectroelectrochemistry Of Cathode Materials In Lithium-Ion Batteries, Lu-Lu Chen, Hao-Ran Li, Wei-Yi Liu, Wei Wang

Journal of Electrochemistry

Developing in situ spectroelectrochemistry methods, which can provide detailed information about species transformation during electrochemical reactions, is very important for studying electrode reaction mechanisms and improving battery performance. Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials, thus, in situ and in operando characterization techniques are particularly important. However, batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells, and there is still much room for battery characterizations. In this work, a specially designed battery …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Physics Undergraduate Honors Theses

Mechanical Exfoliation

Encapsulated 2d Materials And The Potential For 1d Electrical Contacts, Sarah Wittenburg

Physics Undergraduate Honors Theses

The utilization of two-dimensional materials and heterostructures, particularly graphene and hexagonal boron nitride, have garnered significant attention in the realm of nanoelectronics due to their unique properties and versatile functionalities. This study focuses on the synthesis and fabrication processes of monolayer graphene encapsulated between layers of hBN, aiming to explore the potential of these heterostructures for various electronic applications. The encapsulation of graphene within hBN layers not only enhances device performance but also shields graphene from environmental contaminants, ensuring long-term stability. Experimental techniques, including mechanical exfoliation and stamp-assisted transfer, are employed to construct three-layer stacks comprising hBN-graphene-hBN. The fabrication process …

The Analysis Of Mechanical Exfoliation Of Graphene For Various Fabrication And Automation Techniques, Lance Yarbrough

Mechanical Engineering Undergraduate Honors Theses

Mechanical Exfoliation of Graphene is an often-overlooked portion of the fabrication of quantum devices, and to create more devices quickly, optimizing this process to generate better flakes is critical. In addition, it would be valuable to simulate test pulls quickly, to gain insight on flake quality of various materials and exfoliation conditions. Physical pulls of graphene at various temperatures, pull forces, and pull repetitions were analyzed and compared to the results of ANSYS simulations, solved for similar results. Using ANSYS’ ability to predict trends in exfoliations, flake thickness and coverage using stress and deflection analyses were investigated. Generally, both strongly …

Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]

Faculty Publications

Zinc germanium diphosphide (ZnGeP₂) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP₂ crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the …

Shorting At Long Duration: Impact Of Extended Discharge Capacity On Battery Solid Electrolytes, Ryan C. Hill, Amanda S. Peretti, Leo J. Small, Erik D. Spoerke, Yang-Tse Cheng

Chemical and Materials Engineering Faculty Publications

Long-duration energy storage (LDES) is critical to a stable, resilient, and decarbonized electric grid. While batteries are emerging as important LDES devices, extended, high-power discharges necessary for cost-competitive LDES present new materials challenges. Focusing on a new generation of low-temperature molten sodium batteries, we explore here unique phenomena related to long-duration discharge through a well-known solid electrolyte, NaSICON. Specifically, molten sodium symmetric cells at 110 ° C were cycled at 0.1 A cm−2 for 1–23 h discharges. Longer discharges led to unstable overpotentials, reduced resistances, and decreased electrolyte strength, caused by massive sodium penetration not observed in shorter duration discharges. …

Recent Advances In Solar Photo(Electro)Catalytic Nitrogen Fixation, Jun-Bo Ma, Sheng Lin, Zhiqun Lin, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

Ammonia (NH₃) is an essential chemical in modern society. It is currently produced in industry by the Haber-Bosch process using H₂ and N₂ as reactants in the presence of iron-based catalysts at high-temperature (400–600 ^oC) and extremely highpressure (20–40 MPa) conditions. However, its efficiency is limited to 10% to 15%. At the same time, a large amount of energy is consumed, and CO₂ emission is inevitably. The development of a sustainable, clean, and environmentally friendly energy system represents a key strategy to address energy crisis and environmental pollution, ultimately aiming to achieve carbon neutrality. …

Effect Of Fabrication Parameters On The Ferroelectricity Of Hafnium Zirconium Oxide Films: A Statistical Study, Guillermo A. Salcedo, Ahmad E. Islam, Elizabeth Reichley, Michael Dietz, Christine M. Schubert Kabban, Kevin D. Leedy, Tyson C. Back, Weison Wang, Andrew Green, Timothy S. Wolfe, James M. Sattler

Faculty Publications

Ferroelectricity in hafnium zirconium oxide (Hf_1−xZr_xO₂) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf_1−xZr_xO₂ require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (t_f), and annealing temperature (T_a) with the remanent polarization (P_r) in tungsten (W)-capped Hf_1−xZr_xO₂. …