Download or read book Energetics and Dynamics in Quantum Confined Semiconductor Nanostructures written by Jessica Hoy and published by . This book was released on 2013 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to tune the band-gap energies of semiconductor quantum dots, nanoplatelets, and quantum wires, their significant absorption cross sections, and high photoluminescence quantum yields make these nanostructures promising moieties for use in optoelectronic devices, solar concentrators, chemical sensors, and biological labels. The variable dynamics of the electron-hole pairs that occur within semiconductor nanostructures, however, can complicate the utility of these devices. The variability of the dynamics is born from the different paths accessible for the charge carriers to undergo. In this work, three pathways are proposed to be of primary consequence, namely, electronic intraband relaxation, coupling to surface-mediated processes, and tunneling to the external environment. The relative dominance of these paths will vary from sample to sample. More importantly, within a sample, the contributions of the available pathways are found to change with changes in excitation energy. To this end, I investigated the dependence of the ensemble photoluminescence (PL) quantum yields (QYs) on excitation energy for numerous semiconductor nanoparticles with quantum confinement in varying dimensions. A strong dependence of the PL QY on excitation energy is observed in quantum dots (QDs), nanoplatelets (NPLs), and quantum wires (QWs). The highest PL QYs are within the first 300 meV above the band edge, and there is a severe drop in the PL QY towards the highest excitation energies investigated, ~3.1 eV. These high PL QYs are 91 % for CdSe/ZnS QDs, 24 % in CdSe NPLs, which are dispersed in toluene and 25 % in CdTe/CdS QWs, which is dispersed in TOP. These values drop to 12, 8, and 8 % by 3.1 eV, respectively. There are some recognized trends to the shape of this dependency. Local minima in PL QY values occur when intraband relaxation is restricted and ligand or surface mediated transitions are available. These variations in PL QY are reduced when a shell is added to produce a type-I heterostructure. This trend is realized in both QDs and QWs. However, QWs are more weakly confined systems with large surface areas. Their saw-like densities of states that result from the long, unconfined dimension of the QWs and increased valence state mixing yields a higher density of states which leads to a smoother PL QY dependence of the excitation energy. The minimal undulations in the PL QYs that do still exist in these QWs, are further minimized with the addition of a shell to create a type-I heterostructure. Conversely, the pseudo-2D confinement and atomic flatness of NPLs results in narrow, discrete bands of states separated by large energies, ~ 200 meV. This electronic structure restricts intraband relaxation and promotes coupling to other pathways that sponsor non-radiative recombination even more efficiently than QDs. In all samples, exciting with high energies severely diminishes PL QYs as these energies generate highly excited charge-carriers that can access solvent/environmental pathways.
Download or read book Electron and Photon Confinement in Semiconductor Nanostructures written by Benoît Deveaud and published by IOS Press. This book was released on 2003 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this course was to give an overview of the physics of artificial semiconductor structures confining electrons and photons. It furnishes the background for several applications in particular in the domain of optical devices, lasers, light emitting diodes or photonic crystals. The effects related to the microactivity polaritons, which are mixed electromagnetic radiation-exciton states inside a semiconconductor microactivity are covered. The study of the characteristics of such states shows strong relations with the domain of cavity quantum electrodynamics and thus with the investigation of some fundamental theoretical concepts.
Download or read book Nanostructured and Photoelectrochemical Systems for Solar Photon Conversion written by Mary D. Archer and published by World Scientific. This book was released on 2008 with total page 781 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, expert authors describe advanced solar photon conversion approaches that promise highly efficient photovoltaic and photoelectrochemical cells with sophisticated architectures on the one hand, and plastic photovoltaic coatings that are inexpensive enough to be disposable on the other. Their leitmotifs include light-induced exciton generation, junction architectures that lead to efficient exciton dissociation, and charge collection by percolation through mesoscale phases. Photocatalysis is closely related to photoelectrochemistry, and the fundamentals of both disciplines are covered in this volume.
Download or read book Semiconductor Nanocrystals written by Alexander L. Efros and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A physics book that covers the optical properties of quantum-confined semiconductor nanostructures from both the theoretical and experimental points of view together with technological applications. Topics to be reviewed include quantum confinement effects in semiconductors, optical adsorption and emission properties of group IV, III-V, II-VI semiconductors, deep-etched and self assembled quantum dots, nanoclusters, and laser applications in optoelectronics.
Download or read book Semiconductor Quantum Dots written by Yasuaki Masumoto and published by Springer Science & Business Media. This book was released on 2002-05-28 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growth of Self Organized Quantum Dots / J.-S. Lee / - Excitonic Structures and Optical Properties of Quantum Dots / Toshihide Takagahara / - Electron-Phonon Interactions in Semiconductor Quantum Dots / Toshihide Takagahara / - Micro-Imaging and Single Dot Spectroscopy of Self Assembled Quantum Dots / Mitsuru Sugisaki / - Persistent Spectral Hole Burning in Semiconductor Quantum Dots / Yasuaki Masumoto / - Dynamics of Carrier Relaxation in Self Assembled Quantum Dots / Ivan V. Ignatiev, Igor E. Kozin / - Resonant Two-Photon Spectroscopy of Quantum Dots / Alexander Baranov / - Homogeneous Width of Confined Excitons in Quantum Dots - Experimental / Yasuaki Masumoto / - Theory of Exciton Dephasing in Semiconductor Quantum Dots / Toshihide Takagahara / - Excitonic Optical Nonlinearity and Weakly Correlated Exciton-Pair States / Selvakumar V. Nair, Toshihide Takagahara / - Coulomb Effects in the Optical Spectra of Highly Excited Semiconductor Quantum Dots / Selvakumar V. Nair / - Device ...
Download or read book Non Equilibrium Dynamics of Semiconductors and Nanostructures written by Kong-Thon Tsen and published by CRC Press. This book was released on 2018-10-03 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of the femto-second laser has enabled us to observe phenomena at the atomic timescale. One area to reap enormous benefits from this ability is ultrafast dynamics. Collecting the works of leading experts from around the globe, Non-Equilibrium Dynamics of Semiconductors and Nanostructures surveys recent developments in a variety of areas in ultrafast dynamics. In eight authoritative chapters illustrated by more than 150 figures, this book spans a broad range of new techniques and advances. It begins with a review of spin dynamics in a high-mobility two-dimensional electron gas, followed by the generation, propagation, and nonlinear properties of high-amplitude, ultrashort strain solitons in solids. The discussion then turns to nonlinear optical properties of nanoscale artificial dielectrics, optical properties of GaN self-assembled quantum dots, and optical studies of carrier dynamics and non-equilibrium optical phonons in nitride-based semiconductors. Rounding out the presentation, the book examines ultrafast non-equilibrium electron dynamics in metal nanoparticles, monochromatic acoustic phonons in GaAs, and electromagnetically induced transparency in semiconductor quantum wells. With its pedagogical approach and practical, up-to-date coverage, Non-Equilibrium Dynamics of Semiconductors and Nanostructures allows you to easily put the material into practice, whether you are a seasoned researcher or new to the field.
Download or read book Semiconductor Nanostructures written by Dieter Bimberg and published by Springer Science & Business Media. This book was released on 2008-06-03 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing the size of a coherently grown semiconductor cluster in all three directions of space to a value below the de Broglie wavelength of a charge carrier leads to complete quantization of the energy levels, density of states, etc. Such “quantum dots” are more similar to giant atoms in a dielectric cage than to classical solids or semiconductors showing a dispersion of energy as a function of wavevector. Their electronic and optical properties depend strongly on their size and shape, i.e. on their geometry. By designing the geometry by controlling the growth of QDs, absolutely novel possibilities for material design leading to novel devices are opened. This multiauthor book written by world-wide recognized leaders of their particular fields and edited by the recipient of the Max-Born Award and Medal 2006 Professor Dieter Bimberg reports on the state of the art of the growing of quantum dots, the theory of self-organised growth, the theory of electronic and excitonic states, optical properties and transport in a variety of materials. It covers the subject from the early work beginning of the 1990s up to 2006. The topics addressed in the book are the focus of research in all leading semiconductor and optoelectronic device laboratories of the world.
Download or read book Quantum Wells Wires and Dots written by Paul Harrison and published by John Wiley & Sons. This book was released on 2016-04-29 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Wells, Wires and Dots provides all the essential information, both theoretical and computational, to develop an understanding of the electronic, optical and transport properties of these semiconductor nanostructures. The book will lead the reader through comprehensive explanations and mathematical derivations to the point where they can design semiconductor nanostructures with the required electronic and optical properties for exploitation in these technologies. This fully revised and updated 4th edition features new sections that incorporate modern techniques and extensive new material including: Properties of non-parabolic energy bands Matrix solutions of the Poisson and Schrödinger equations Critical thickness of strained materials Carrier scattering by interface roughness, alloy disorder and impurities Density matrix transport modelling Thermal modelling Written by well-known authors in the field of semiconductor nanostructures and quantum optoelectronics, this user-friendly guide is presented in a lucid style with easy to follow steps, illustrative examples and questions and computational problems in each chapter to help the reader build solid foundations of understanding to a level where they can initiate their own theoretical investigations. Suitable for postgraduate students of semiconductor and condensed matter physics, the book is essential to all those researching in academic and industrial laboratories worldwide. Instructors can contact the authors directly ([email protected] / [email protected]) for Solutions to the problems.
Download or read book Semiconductor Nanophotonics written by Michael Kneissl and published by Springer Nature. This book was released on 2020-03-10 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the state-of-the-art in the development of semiconductor nanostructures and nanophotonic devices. It covers epitaxial growth processes for GaAs- and GaN-based quantum dots and quantum wells, describes the fundamental optical, electronic, and vibronic properties of nanomaterials, and addresses the design and realization of various nanophotonic devices. These include energy-efficient and high-speed vertical cavity surface emitting lasers (VCSELs) and ultra-small metal-cavity nano-lasers for applications in multi-terabus systems; silicon photonic I/O engines based on the hybrid integration of VCSELs for highly efficient chip-to-chip communication; electrically driven quantum key systems based on q-bit and entangled photon emitters and their implementation in real information networks; and AlGaN-based deep UV laser diodes for applications in medical diagnostics, gas sensing, spectroscopy, and 3D printing. The experimental results are accompanied by reviews of theoretical models that describe nanophotonic devices and their base materials. The book details how optical transitions in the active materials, such as semiconductor quantum dots and quantum wells, can be described using a quantum approach to the dynamics of solid-state electrons under quantum confinement and their interaction with phonons, as well as their external pumping by electrical currents. With its broad and detailed scope, this book is indeed a cutting-edge resource for researchers, engineers and graduate-level students in the area of semiconductor materials, optoelectronic devices and photonic systems.
Download or read book Characterization of Semiconductor Heterostructures and Nanostructures written by S. Sanguinetti and published by Elsevier Inc. Chapters. This book was released on 2013-04-11 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Materials Lateral Semiconductor Nanostructures Hybrid Systems and Nanocrystals written by Detlef Heitmann and published by Springer Science & Business Media. This book was released on 2010-08-20 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanostructures are ideal systems to tailor the physical properties via quantum effects, utilizing special growth techniques, self-assembling, wet chemical processes or lithographic tools in combination with tuneable external electric and magnetic fields. Such systems are called "Quantum Materials".The electronic, photonic, and phononic properties of these systems are governed by size quantization and discrete energy levels. The charging is controlled by the Coulomb blockade. The spin can be manipulated by the geometrical structure, external gates and by integrating hybrid ferromagnetic emitters.This book reviews sophisticated preparation methods for quantum materials based on III-V and II-VI semiconductors and a wide variety of experimental techniques for the investigation of these interesting systems. It highlights selected experiments and theoretical concepts and gives such a state-of-the-art overview about the wide field of physics and chemistry that can be studied in these systems.
Download or read book Quantum Confined Semiconductor Nanostructures Volume 737 written by Victor I. Klimov and published by Cambridge University Press. This book was released on 2003-04-16 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners. This book brings together a single comprehensive overview of recent progress and future directions in nanoscale semiconductor research. Fields ranging from materials science to physics, chemistry, electrical and microelectronic engineering, circuit design, and more, are represented.
Download or read book Quantum Confined Semiconductor Nanocrystals written by Wesley Chiang and published by American Chemical Society. This book was released on 2023-09-26 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, the fascinating story of colloidal quantum dots has no series finale yet. Instead, there continue to be advancements in our understanding of the fundamental properties of these nanocrystals, each of these advancements catalyzing a spin-off into a new journey toward potential applications. These remarkable advancements include improving the synthesis techniques, characterizing nanocrystals at the single-particle level, and tailoring their properties for specific applications. The quantum-confined colloidal semiconductor nanocrystals field has witnessed a remarkable convergence of nanoscience, materials chemistry, and spectroscopy, resulting in unprecedented control over their properties. With ongoing research efforts, the potential of semiconductor nanocrystals continues to unfold. Scientists are exploring new materials, developing scalable synthesis methods, and pushing the boundaries of their applications in fields such as quantum computing, energy storage, and biological sensing. The authors take the reader into quantum confinement and quantum dots. While the contents of this primer are rather expansive, they merely scratch the surface of the complex voyage that quantum dot sciences have undergone. The authors have identified vital terminology, valuable concepts, techniques, and applications.
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 Phonons in Semiconductor Nanostructures written by J.P. Leburton and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last ten years, the physics and technology of low dimensional structures has experienced a tremendous development. Quantum structures with vertical and lateral confinements are now routinely fabricated with feature sizes below 100 run. While quantization of the electron states in mesoscopic systems has been the subject of intense investigation, the effect of confinement on lattice vibrations and its influence on the electron-phonon interaction and energy dissipation in nanostructures received atten tion only recently. This NATO Advanced Research Workshop on Phonons in Sem iconductor Nanostructures was a forum for discussion on the latest developments in the physics of phonons and their impact on the electronic properties of low-dimensional structures. Our goal was to bring together specialists in lattice dynamics and nanos tructure physics to assess the increasing importance of phonon effects on the physical properties of one-(lD) and zero-dimensional (OD) structures. The Workshop addressed various issues related to phonon physics in III-V, II-VI and IV semiconductor nanostructures. The following topics were successively covered: Models for confined phonons in semiconductor nanostructures, latest experimental observations of confined phonons and electron-phonon interaction in two-dimensional systems, elementary excitations in nanostructures, phonons and optical processes in reduced dimensionality systems, phonon limited transport phenomena, hot electron effects in quasi - ID structures, carrier relaxation and phonon bottleneck in quantum dots.
Download or read book Charge Carrier Dynamics of Quantum Confined Semiconductor Nanoparticles Analyzed Via Transient Absorption Spectroscopy written by Arthur Joseph Thibert (III) and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The slower kinetics observed for the TBA2Ti4O9 nanosheets originates either from the presence of deeper trap sites on the sheets vs. the nanoparticles, more trap sites, or from more effective electron-hole separation because of the micrometer dimensions of the 2D lattice. Appendix II, depicts the visible solar spectrum at sea level detailing the percentage of photons and energy that exist within certain wavelength ranges.
Download or read book Ultrafast Dynamics In Molecules Nanostructures And Interfaces Selected Lectures Presented At Symposium On Ultrafast Dynamics Of The 7th International Conference On Materials For Advanced Technologies written by Guglielmo Lanzani and published by World Scientific. This book was released on 2014-01-22 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Primary events in natural systems or devices occur on extremely short time scales, and yet determine in many cases the final performance or output. For this reason research in ultrafast science is of primary importance and impact in both fundamental research as well as its applications. This book reviews the advances in the field, addressing timely and open questions such as the role of quantum coherence in biology, the role of excess energy in electron injection at photovoltaic interfaces or the dynamics in quantum confined structures (e.g. multi carrier generation). The approach is that of a monograph, with a broad tutorial introduction and an overview of the recent results. This volume includes selected lectures presented at Symposium on Ultrafast Dynamics of the 7th International Conference on Materials for Advanced Technologies.
