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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
Control Of Majorana Edge Modes By A G-Factor Engineered Nanowire Spin Transistor, Amrit De, Alexey Kovalev
Control Of Majorana Edge Modes By A G-Factor Engineered Nanowire Spin Transistor, Amrit De, Alexey Kovalev
Department of Physics and Astronomy: Faculty Publications
We propose the manipulation of Majorana edge states via hybridization and spin currents in a nanowire spin transistor. The spin transistor is based on a heterostructure nanowire comprising of semiconductors with large and small g-factors that form the topological and non-topological regions respectively. The hybridization of bound edge states results in spin currents and 4π-periodic torques, as a function of the relative magnetic field angle – an effect which is dual to the fractional Josephson effect. We establish relation between torques and spin-currents in the non-topological region where the magnetic field is almost zero and spin is …
Two-Dimensional Electron Gases At The Surface Of Potassium Tantalate, Ben Pound
Two-Dimensional Electron Gases At The Surface Of Potassium Tantalate, Ben Pound
Ben Pound
No abstract provided.
Two-Dimensional Electron Gases At The Surface Of Potassium Tantalate, Ben Pound
Two-Dimensional Electron Gases At The Surface Of Potassium Tantalate, Ben Pound
Browse All Undergraduate research
No abstract provided.
Investigation Of Carrier Transit Motion In Pcdtbt By Optical Shg Technique, Shahino Mah Abdullah
Investigation Of Carrier Transit Motion In Pcdtbt By Optical Shg Technique, Shahino Mah Abdullah
Shahino Mah Abdullah
We analyze the carrier transit behavior in poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), which has been reported as a donor material for efficient bulk hetero junction photovolatic devices. The transfer and transient carrier mobilities in the PCDTBT thin films have been measured and analyzed. The transfer mobility has been measured by the transfer curve of the OFET, whereas, the transient mobility is recorded using a time-resolved electric-field-induced optical second-harmonic-generation (TRM-SHG) technique. Using TRM-SHG technique, the dynamic motion of the charge carriers in the PCDTBT thin films has been directly visualized. We anticipate that the analysis of the carrier motion by TRM-SHG, will be effective …
Below Gap Optical Absorption In Gaas Driven By Intense, Single-Cycle Coherent Transition Radiation, J. Goodfellow, Matthias Fuchs, D. Daranciang, S. Ghimire, F. Chen, H. Loos, D. A. Reis, A. S. Fisher, A. M. Lindenberg
Below Gap Optical Absorption In Gaas Driven By Intense, Single-Cycle Coherent Transition Radiation, J. Goodfellow, Matthias Fuchs, D. Daranciang, S. Ghimire, F. Chen, H. Loos, D. A. Reis, A. S. Fisher, A. M. Lindenberg
Matthias Fuchs Publications
Single-cycle terahertz fields generated by coherent transition radiation from a relativistic electron beam are used to study the high field optical response of single crystal GaAs. Large amplitude changes in the sub-band-gap optical absorption are induced and probed dynamically by measuring the absorption of a broad-band optical beam generated by transition radiation from the same electron bunch, providing an absolutely synchronized pump and probe geometry. This modification of the optical properties is consistent with strong-field-induced electroabsorption. These processes are pertinent to a wide range of nonlinear terahertz-driven lightmatter interactions anticipated at accelerator-based sources.
Cytotoxicity Of Zno Nanoparticles Can Be Tailored By Modifying Their Surface Structure: A Green Chemistry Approach For Safer Nanomaterials, Alex Punnoose, Kelsey Dodge, John W. Rasmussen, Jordan Chess, Denise Wingett, Catherine Anders
Cytotoxicity Of Zno Nanoparticles Can Be Tailored By Modifying Their Surface Structure: A Green Chemistry Approach For Safer Nanomaterials, Alex Punnoose, Kelsey Dodge, John W. Rasmussen, Jordan Chess, Denise Wingett, Catherine Anders
Physics Faculty Publications and Presentations
ZnO nanoparticles (NP) are extensively used in numerous nanotechnology applications; however, they also happen to be one of the most toxic nanomaterials. This raises significant environmental and health concerns and calls for the need to develop new synthetic approaches to produce safer ZnO NP, while preserving their attractive optical, electronic, and structural properties. In this work, we demonstrate that the cytotoxicity of ZnO NP can be tailored by modifying their surface-bound chemical groups, while maintaining the core ZnO structure and related properties. Two equally sized (9.26 ± 0.11 nm) ZnO NP samples were synthesized from the same zinc acetate precursor …
Investigation Of Charge Transport In Organic Polymer Donor/Acceptor Photovolatic Materials, Zubair Ahmad, Shahino Mah Abdullah, Khaulah Sulaiman
Investigation Of Charge Transport In Organic Polymer Donor/Acceptor Photovolatic Materials, Zubair Ahmad, Shahino Mah Abdullah, Khaulah Sulaiman
Shahino Mah Abdullah
Pi-conjugated organic semiconductors have long been used as either holes or electrons transport materials. Recently ambipolar charge carrier transport in these materials have been reported in many investigations. In this paper, we report on the basis of experimental results that the organic semiconductor (donor/acceptor) materials can be as good electrons transporters as these materials are holes transporters. In our study, the solution-processed unipolar diodes based on organic materials P3HT, VOPCPhO and their blends with PCBM have been fabricated. The I-V characteristics of these diodes have been analyzed in the space charge limited current regime. The values of the electron and …
Investigation Of Charge Transport In Organic Polymer Donor/Acceptor Photovolatic Materials, Zubair Ahmad, Shahino Mah Abdullah, Khaulah Sulaiman
Investigation Of Charge Transport In Organic Polymer Donor/Acceptor Photovolatic Materials, Zubair Ahmad, Shahino Mah Abdullah, Khaulah Sulaiman
Zubair Ahmad
Pi-conjugated organic semiconductors have long been used as either holes or electrons transport materials. Recently ambipolar charge carrier transport in these materials have been reported in many investigations. In this paper, we report on the basis of experimental results that the organic semiconductor (donor/acceptor) materials can be as good electrons transporters as these materials are holes transporters. In our study, the solution-processed unipolar diodes based on organic materials P3HT, VOPCPhO and their blends with PCBM have been fabricated. The I-V characteristics of these diodes have been analyzed in the space charge limited current regime. The values of the electron and …
Effects Of Bandgap On Secondary Electron Emission For Graphitic Carbon Semiconductiors, Jodie Gillespie, Jr Dennison
Effects Of Bandgap On Secondary Electron Emission For Graphitic Carbon Semiconductiors, Jodie Gillespie, Jr Dennison
Jodie Corbridge Gillespie
Preliminary data indicates a relationship between bandgap width and magnitude of secondary electron (SE) yield. Our work extends this research to investigate the correlation of small bandgap width to SE yield. These trends are compared with current semiempirical models of two limiting cases, conductors and large bandgap semiconductors. Specifically, five graphitic amorphous carbon (g-C) samples of decreasing bandgap width were produced by vacuum annealing from 0C-1050C. Preliminary data shows a 30of g-C above nanocrystalline graphite. Measurements include SE yields, backscattered yields and electron emission spectra, as well as characterization with SEM, photoyields, AES, resistivity, and Raman spectroscopy. SE yields were …
Temperature Dependence Of Defect-Related Photoluminescence In Iii-V And Ii-Vi Semiconductors, Michael A. Reshchikov
Temperature Dependence Of Defect-Related Photoluminescence In Iii-V And Ii-Vi Semiconductors, Michael A. Reshchikov
Physics Publications
Mechanisms of thermal quenching of photoluminescence (PL) related to defects insemiconductors are analyzed. We conclude that the Schön-Klasens (multi-center) mechanism of the thermal quenching of PL is much more common for defects in III–V and II–VI semiconductorsas compared to the Seitz-Mott (one-center) mechanism. The temperature dependencies of PLare simulated with a phenomenological model. In its simplest version, three types of defects are included: a shallow donor, an acceptor responsible for the PL, and a nonradiative center that has the highest recombination efficiency. The case of abrupt and tunable thermal quenching ofPL is considered in more detail. This phenomenon is predicted …
Time-Resolved Photoluminescence From Defects In N-Type Gan, Michael A. Reshchikov
Time-Resolved Photoluminescence From Defects In N-Type Gan, Michael A. Reshchikov
Physics Publications
Point defects in GaN were studied with time-resolved photoluminescence (PL). The effects of temperature and excitation intensity on defect-related PL have been investigated theoretically and experimentally. A phenomenological model, based on rate equations, explains the dependence of the PL intensity on excitation intensity, as well as the PL lifetime and its temperature dependence. We demonstrate that time-resolved PL measurements can be used to find the concentrations of free electrons and acceptors contributing to PL in n-type semiconductors.
Processing Of Germanium For Integrated Circuits, Ray Duffy, Maryam Shayesteh, Ran Yu
Processing Of Germanium For Integrated Circuits, Ray Duffy, Maryam Shayesteh, Ran Yu
Turkish Journal of Physics
In this review paper the authors will focus on Ge processing for integrated circuits. The key areas that require the most attention are substrates and integration, gate dielectrics, and access resistance. We will discuss each of these topics in turn, while also reviewing the most scaled Ge field-effect-transistor devices, and consider how modelling activities have matured for Ge in recent years.
Fundamental Studies Of Supported Graphene Interfaces : Defect Density Of States In Graphene Field Effect Transistors (Fets) And Ideal Graphene - Silicon Schottky Diodes, Dhiraj Sinha
Legacy Theses & Dissertations (2009 - 2024)
The physics of transport in atomically thin 2D materials is an active area of research, important for understanding fundamental properties of reduced dimensional materials and for applications. New phenomena based on graphene may include properties of topologically protected insulators. Applications of these materials are envisioned in electronics, optoelectronics and spintronics.