Download or read book Theoretical Insight Into the Manipulation of the Optical and Magnetic Properties of Transition metal doped II VI Semiconductor Quantum Dots written by Joseph William May and published by . This book was released on 2014 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to tune the electronic, magnetic, and optical properties of II-VI semiconductor quantum dots (QDs) makes these materials ideal candidates in the fabrication of new solar energy, spin electronic, and phosphorescent devices. This dissertation makes use of electronic structure theory to provide insight into the physical underpinnings of magnetic exchange and photoexcitation in Mn2[superscript +]- and Co2[superscript +]-doped CdSe and ZnO QDs. Specifically, new methods for controlling these physical effects via the incorporation of various dopants or changes in the QD's size and shape are presented. Several examples of these control techniques are discussed in this dissertation. Ferromagnetic alignment of multiple unpaired Mn2[superscript +] 3d electrons is predicted when the p-type defect N2[superscript - ] is present in ZnO QDs. Control over the magnetic exchange interactions between charge carriers and TM2[superscript] dopants that give rise to ferromagnetism is achieved by distorting the QD's shape along one or two dimensions. Aliovalent doping with Al3[superscript +] produces QDs that are spectroscopically identical to photochemically charged QDs, yet exhibit different reactivities. A unique temperature dependence of the luminescence and photoconductivity in large Co2[superscript +] -doped ZnO QDs is predicted upon excitation of its mid-gap excited state. Lastly, a new method for the optimization of transition state molecular geometries is shown to exhibit fast optimization and to be advantageous for difficult optimizations where the reaction path is flat, ideal for optimizing large QD structures.

Download or read book Rare Earth and Transition Metal Doping of Semiconductor Materials written by Volkmar Dierolf and published by Woodhead Publishing. This book was released on 2016-01-23 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rare Earth and Transition Metal Doping of Semiconductor Material explores traditional semiconductor devices that are based on control of the electron's electric charge. This book looks at the semiconductor materials used for spintronics applications, in particular focusing on wide band-gap semiconductors doped with transition metals and rare earths. These materials are of particular commercial interest because their spin can be controlled at room temperature, a clear opposition to the most previous research on Gallium Arsenide, which allowed for control of spins at supercold temperatures. Part One of the book explains the theory of magnetism in semiconductors, while Part Two covers the growth of semiconductors for spintronics. Finally, Part Three looks at the characterization and properties of semiconductors for spintronics, with Part Four exploring the devices and the future direction of spintronics. - Examines materials which are of commercial interest for producing smaller, faster, and more power-efficient computers and other devices - Analyzes the theory behind magnetism in semiconductors and the growth of semiconductors for spintronics - Details the properties of semiconductors for spintronics

Download or read book First Principle Vs Experimental Design of Diluted Magnetic Semiconductors written by Omar Mounkachi and published by Nova Science Publishers. This book was released on 2018-10 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent discoveries have given rise to a new class of electronics known as "spin electronics or spintronics," which uses the electron spin rather than its charge to create polarized currents. Spintronics is currently experiencing an extraordinary development with the manufacture of nanoscale devices based on ferromagnetic materials and semiconductors. Their applications are numerous, ranging from recording, electronics, and optoelectronics to quantum information. Spintronics is a new generation of electronics that has brought and continues to bring a lot of progress to information storage; this is due to the discovery of new materials with new functionalities and multiple applications. The discovery of giant magnetoresistance (GMR) in 1988 by Albert Fert and Peter Grünberg (receiver of the Nobel Prize in Physics in 2007) is considered a starting point of spintronics. GMR is based on the variation of the electric current in the presence of a magnetic field. The spintronics has made important contributions to the miniaturization desired for electronics; it uses nanometric components for processing and storing information. However, the limits of miniaturization on a nanometric scale are known, and it is imperative to develop new ways and new materials to exceed those limits. The most desired properties for these materials are high spin polarization, modular magnetic properties by an electric field and a long lifetime of the spin polarization. Among the new promising materials, we cite the following: Diluted magnetic semiconductors, which give new magnetic properties of conventional semiconductors, functional oxides (including the semi-metals and multiferroic metals) and organic semiconductors. The main theoretical challenge in this area is to understand how the macroscopic magnetic behavior observed results from interactions of a large number of degrees of microscopic freedom. In these systems the disorder is an essential parameter of magnetic phenomena, and due to random locations of impurity atoms it can lead to a total physical difference from the observed absence. There has been considerable recent advances in the design of these materials as diluted magnetic semiconductors (DMS, or diluted magnetic semiconductors), and a number of semiconductors were investigated as II-VI group and III-V group doped compounds, with transition metals substituting their original cations. There are several different theoretical approaches to study these magnetic materials. The ab-initio approach starts from the Schrödinger equation to simulate a given material. Such an approach is essential to determine the parameters and microscopic properties of such a system. In this book, the authors analyzed the electronic structure of magnetic semiconductors diluted in the case of ZnO, GaN, SnO2, TiO2, MgH2, EuO and EuN doped RENs (RE=GdN, DyN and HoN). The authors focused on magnetic, optical and exchange mechanisms which control the ferromagnetism in these systems. The purpose of this book is to propose some ideas to answer the most important question in material science for semiconductor spintronics, primarily considering how room-temperature ferromagnetism in DMS can be realized. Additionally, the correlation between first principle and experimental design to see how properties of yet-to-be-synthesized materials can be predicted is discussed.

Download or read book Localisation and Interaction written by D.M. Finlayson and published by CRC Press. This book was released on 1986-01-01 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Localisation and Interaction covers the scaling theory of localization metal-insulator transitions, two-dimensional systems, interaction effects in impure metals, weak localization, critical point measurement, quantum wells, integer quantum Hall effects, magnetic field induced transitions, static and dynamic magnetic probes, band gap narrowing, and an experiment with the quantum Hall effects.

Download or read book Transition Metal Compounds written by Sajjad Haider and published by BoD – Books on Demand. This book was released on 2021-06-09 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores synthesis, structural changes, properties, and potential applications of transition metal (TM) compounds. Over three sections, chapters cover such topics as the synthesis of pentoxide vanadium (V2O5), the effect of TM compounds on structural, dielectric properties and high-temperature superconductors, and TM-doped nanocrystals (NCs).

Download or read book Magnetic Properties of Layered Transition Metal Compounds written by L.J. de Jongh and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades low-dimensional (low-d) physics has matured into a major branch of science. Quite generally we may define a system with restricted dimensionality d as an object that is infinite only in one or two spatial directions (d = 1 and 2). Such a definition comprises isolated single chains or layers, but also fibres and thin layers (films) of varying but finite thickness. Clearly, a multitude of physical phenomena, notably in solid state physics, fall into these categories. As examples, we may mention: • Magnetic chains or layers (thin-film technology). • Metallic films (homogeneous or heterogeneous, crystalline, amorphous or microcristalline, etc.). • I-d or 2-d conductors and superconductors. • Intercalated systems. • 2-d electron gases (electrons on helium, semiconductor interfaces). • Surface layer problems (2-d melting of monolayers of noble gases on a substrate, surface problems in general). • Superfluid films of ~He or 'He. • Polymer physics. • Organic and inorganic chain conductors, superionic conductors. • I-d or 2-d molecular crystals and liquid crystals. • I-d or 2-d ferro- and antiferro electrics.

Download or read book Multi Frequency EPR Spectroscopy of Conjugated Polymers and Their Nanocomposites written by Victor I. Krinichnyi and published by CRC Press. This book was released on 2016-10-14 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conjugated polymeric materials and their nanocomposites are widely used for the creation of alternative sources of renewable energy, cell phone screens, mobile gadgets, video players and OLED-TV, as well as organic diodes, transistors, sensors, etc. with field-dependent and spin-assisted electronic properties. Multifrequency EPR Spectroscopy methods can help researchers optimize their structural, magnetic and electronic properties for the creation of more efficient molecular devices. This book will acquaint the reader with the basic properties of conjugated polymers, the fundamentals of EPR Spectroscopy, and the information that can be obtained at different wavebands of EPR spectroscopy.

Download or read book Thinking about Science written by Ernst Peter Fischer and published by W. W. Norton. This book was released on 1988 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The life of the man who studied astronomy, theoretical physics, contributed to genetics, molecular biology, sensory behavior, and evolution and shared the Nobel Prize for Physiology and Medicine

Download or read book Magneto optical Properties of II VI Semiconductor Colloidal Nanostructure written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantum Effects Heavy Doping And The Effective Mass written by Kamakhya Prasad Ghatak and published by World Scientific. This book was released on 2016-12-08 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of the effective mass (EM) is already well known since the inception of solid-state physics and this first-of-its-kind monograph solely deals with the quantum effects in EM of heavily doped (HD) nanostructures. The materials considered are HD quantum confined nonlinear optical, III-V, II-VI, IV-VI, GaP, Ge, PtSb2, stressed materials, GaSb, Te, II-V, Bi2Te3, lead germanium telluride, zinc and cadmium diphosphides, and quantum confined III-V, II-VI, IV-VI, and HgTe/CdTe super-lattices with graded interfaces and effective mass super-lattices. The presence of intense light waves in optoelectronics and strong electric field in nano-devices change the band structure of semiconductors in fundamental ways, which have also been incorporated in the study of EM in HD quantized structures of optoelectronic compounds that control the studies of the HD quantum effect devices under strong fields. The importance of measurement of band gap in optoelectronic materials under intense external fields has also been discussed in this context. The influences of magnetic quantization, crossed electric and quantizing fields, electric field and light waves on the EM in HD semiconductors and super-lattices are discussed.The content of this book finds twenty-eight different applications in the arena of nano-science and nano-technology. This book contains 200 open research problems which form the integral part of the text and are useful for both PhD aspirants and researchers in the fields of condensed matter physics, materials science, solid state sciences, nano-science and technology and allied fields in addition to the graduate courses in semiconductor nanostructures. The book is written for post-graduate students, researchers, engineers and professionals in the fields of condensed matter physics, solid state sciences, materials science, nanoscience and technology and nanostructured materials in general.

Download or read book Nanocrystal Quantum Dots written by Victor I. Klimov and published by CRC Press. This book was released on 2017-12-19 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of recent advancements in colloidal nanocrystals and quantum-confined nanostructures, Nanocrystal Quantum Dots is the second edition of Semiconductor and Metal Nanocrystals: Synthesis and Electronic and Optical Properties, originally published in 2003. This new title reflects the book’s altered focus on semiconductor nanocrystals. Gathering contributions from leading researchers, this book contains new chapters on carrier multiplication (generation of multiexcitons by single photons), doping of semiconductor nanocrystals, and applications of nanocrystals in biology. Other updates include: New insights regarding the underlying mechanisms supporting colloidal nanocrystal growth A revised general overview of multiexciton phenomena, including spectral and dynamical signatures of multiexcitons in transient absorption and photoluminescence Analysis of nanocrystal-specific features of multiexciton recombination A review of the status of new field of carrier multiplication Expanded coverage of theory, covering the regime of high-charge densities New results on quantum dots of lead chalcogenides, with a focus studies of carrier multiplication and the latest results regarding Schottky junction solar cells Presents useful examples to illustrate applications of nanocrystals in biological labeling, imaging, and diagnostics The book also includes a review of recent progress made in biological applications of colloidal nanocrystals, as well as a comparative analysis of the advantages and limitations of techniques for preparing biocompatible quantum dots. The authors summarize the latest developments in the synthesis and understanding of magnetically doped semiconductor nanocrystals, and they present a detailed discussion of issues related to the synthesis, magneto-optics, and photoluminescence of doped colloidal nanocrystals as well. A valuable addition to the pantheon of literature in the field of nanoscience, this book presents pioneering research from experts whose work has led to the numerous advances of the past several years.

Download or read book Fundamentals of Semiconductors written by Peter YU and published by Springer Science & Business Media. This book was released on 2007-05-08 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excellent bridge between general solid-state physics textbook and research articles packed with providing detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors "The most striking feature of the book is its modern outlook ... provides a wonderful foundation. The most wonderful feature is its efficient style of exposition ... an excellent book." Physics Today "Presents the theoretical derivations carefully and in detail and gives thorough discussions of the experimental results it presents. This makes it an excellent textbook both for learners and for more experienced researchers wishing to check facts. I have enjoyed reading it and strongly recommend it as a text for anyone working with semiconductors ... I know of no better text ... I am sure most semiconductor physicists will find this book useful and I recommend it to them." Contemporary Physics Offers much new material: an extensive appendix about the important and by now well-established, deep center known as the DX center, additional problems and the solutions to over fifty of the problems at the end of the various chapters.

Download or read book Defect Induced Magnetism in Oxide Semiconductors written by Parmod Kumar and published by Elsevier. This book was released on 2023-05-26 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defect-Induced Magnetism in Oxide Semiconductors provides an overview of the latest advances in defect engineering to create new magnetic materials and enable new technological applications. First, the book introduces the mechanisms, behavior, and theory of magnetism in oxide semiconductors and reviews the methods of inducing magnetism in these materials. Then, strategies such as pulsed laser deposition and RF sputtering to grow oxide nanostructured materials with induced magnetism are discussed. This is followed by a review of the most relevant postdeposition methods to induce magnetism in oxide semiconductors including annealing, ion irradiation, and ion implantation. Examples of defect-induced magnetism in oxide semiconductors are provided along with selected applications. This book is a suitable reference for academic researchers and practitioners and for people engaged in research and development in the disciplines of materials science and engineering. - Reviews the magnetic, electrical, dielectric and optical properties of oxide semiconductors with defect-induced magnetism - Discusses growth and post-deposition strategies to grow oxide nanostructured materials such as oxide thin films with defect-induced magnetism - Provides examples of materials with defect-induced magnetism such as zinc oxide, cerium dioxide, hafnium dioxide, and more

Download or read book Crystal Growth Optical Characterization and Lasing of Transition Metal Doped II IV Semiconductors written by Althea G. Bluiett and published by . This book was released on 2003 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cadmium Telluride Quantum Dots written by John Donegan and published by CRC Press. This book was released on 2013-12-03 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, semiconductor quantum dots—small colloidal nanoparticles—have garnered a great deal of scientific interest because of their unique properties. Among nanomaterials, CdTe holds special technological importance as the only known II–VI material that can form conventional p–n junctions. This makes CdTe very important for the development of novel optoelectronic devices such as light-emitting diodes, solar cells, and lasers. Moreover, the demand for water-compatible light emitters and the most common biological buffers give CdTe quantum dots fields a veritable edge in biolabeling and bioimaging. Cadmium Telluride Quantum Dots: Advances and Applications focuses on CdTe quantum dots and addresses their synthesis, assembly, optical properties, and applications in biology and medicine. It makes for a very informative reading for anyone involved in nanotechnology and will also benefit those scientists who are looking for a comprehensive account on the current state of quantum dot–related research.

Download or read book Tunable Electronic and Magnetic Properties in 2D WSe2 Monolayer Via Vanadium V Doping and Chalcogenide Se Vacancies written by Dinesh Thapa and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first-principles density functional theory (DFT) was implemented to investigate the structural, electronic and magnetic properties of vanadium (V) substituted and chalcogen (Se) vacancies in tungsten diselenide (WSe 2 ) monolayer, novel two dimensional (2D) monolayer (ML) structures in binary compounds ZnX (X= As, Sb, and Bi), and novel 2D electrides on transition metal-rich mono-oxide or chalcogenides, based on Perdew-Burke-Ernzerhof (PBE) exchange functional employed in Vienna Ab-Initio Simulation Packages (VASP). The inherent defect in 2D transition metal dichalcogenides (TMDCs) contains unavoidable substitutional defects and a certain amount of chalcogen vacancies. This type of defect affects the electronic and magnetic properties of 2D-TMDCs. To account for this fact, we demonstrated using DFT that the V-doped WSe 2 monolayer exhibits long-range ferromagnetic order. Further, the chalcogenide (Se) vacancies clustered around V-atom enhance the ferromagnetic properties of the system consistent with experimental findings. This dissertation explores the important role of Se-vacancies in the magnetic properties of the V-doped WSe 2 monolayer and proposes a method to enhance the magnetic properties of such 2D non-magnetic van der Waal (vdW) materials. In the second study, we have attempted theoretically to engineer the monolayer structure in II-V binary compounds ZnX with orthorhombic symmetry. We proved the dynamical stability of the bulk and ML structures manifested by the absence of imaginary frequencies in phonon dispersion curves. Our calculations on the density of states (DOS), and band structures using GGA indicate the increasing value of bandgap as well as the transition from indirect to direct bandgap while going from bulk to monolayer structure of ZnX. Our theoretical calculations will represent an archetype of novel 2D semiconductors on ZnX. Next, we have tailored using DFT, the structural and electronic properties of the 2D electrides that belong to transition metal-rich mono-oxide and chalcogenides with hexagonal (Hf 2 X; X = O, S, Se, Te), and orthorhombic (Ti2S and Zr2S) symmetry thereby introducing novel electrides to the electride family. The Bader charge analysis, electron localization function (ELF), projected DOS, and the calculated value of low work functions provides sufficient theoretical shreds of evidence to prove these materials as electrides.

Download or read book Semiconductor Nanocrystal Quantum Dots written by Andrey Rogach and published by Springer Science & Business Media. This book was released on 2008-09-02 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to specifically focus on semiconductor nanocrystals, and address their synthesis and assembly, optical properties and spectroscopy, and potential areas of nanocrystal-based devices. The enormous potential of nanoscience to impact on industrial output is now clear. Over the next two decades, much of the science will transfer into new products and processes. One emerging area where this challenge will be very successfully met is the field of semiconductor nanocrystals. Also known as colloidal quantum dots, their unique properties have attracted much attention in the last twenty years.