Download or read book Exciton Dynamics in Semiconductor Quantum Dot Structures written by Matthias Schwab and published by . This book was released on 2005 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Radiationless Transitions written by Sheng Lin and published by Elsevier. This book was released on 2012-12-02 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiationless Transitions is a critical discussion of research studies on the theory and experiments in radiationless transitions. This book is composed of nine chapters, and begins with discussions on the theory and experiment of photophysical processes of single vibronic levels and/or single rovibronic levels. The subsequent chapters deal with the spectroscopic investigations of intramolecular vibrational relaxation; the dynamics of molecular excitation by light; and the photophysical processes of small molecules in condensed phase. The discussions then shift to the high pressure effects on molecular luminescence and the internal conversion involving localized excitations, presenting one qualitative and one quantitative example, as well as the intersystem crossing with localized excitations. A chapter explores the energy transfer processes that occur after a molecule in solution is excited by light, with an emphasis on solid solutions in which the large amplitude molecular motion is largely quenched. This chapter also looks into the liquid solutions in which the molecules can translate and rotate under the influence of fluctuating forces from the liquid. The concluding chapter focuses on ultrafast processes. Researchers in the fields of physics, chemistry, and biology will benefit from this book.
Download or read book Semiconductor Quantum Dots written by Y. Masumoto and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor quantum dots represent one of the fields of solid state physics that have experienced the greatest progress in the last decade. Recent years have witnessed the discovery of many striking new aspects of the optical response and electronic transport phenomena. This book surveys this progress in the physics, optical spectroscopy and application-oriented research of semiconductor quantum dots. It focuses especially on excitons, multi-excitons, their dynamical relaxation behaviour and their interactions with the surroundings of a semiconductor quantum dot. Recent developments in fabrication techniques are reviewed and potential applications discussed. This book will serve not only as an introductory textbook for graduate students but also as a concise guide for active researchers.
Download or read book Colloidal Quantum Dot Optoelectronics and Photovoltaics written by Gerasimos Konstantatos and published by Cambridge University Press. This book was released on 2013-11-07 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: Captures the most up-to-date research in the field, written in an accessible style by the world's leading experts.
Download or read book Using Time resolved Photoluminescence Spectroscopy to Examine Exciton Dynamics in II VI Semiconductor Nanostructures written by Laura M. Robinson and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We use photoluminescence spectroscopy to investigate the optical properties of two different II-VI semiconductor nanostructure systems: ZnMnSe/ZnSe multiple quantum wells and self-assembled CdSe quantum dots. The behavior of excitons in ZnMnSe quantum wells is examined using polarized magneto-photoluminescence, while (temperature-dependent) time-resolved photoluminescence is used to study the dynamics of excitons confined to quantum dot structures. When Zn0.86Mn0.14Se/ZnSe multiple quantum wells are placed in an external magnetic fields, the spin-down holes become confined to the ZnMnSe "barriers," while the electrons remain in the ZnSe "wells." This spatial separation of electrons and holes results in weak electron-hole overlap, which should result in a large increase of the radiative lifetime of the spin-down exciton. As a result, we see the formation of exciton magnetic polarons (EMP) which lower their energy by spontaneously aligning the magnetic impurities in the exciton Bohr radius. We find that the EMP polarization approaches 100% in fields as small as 200 mT in these spatially indirect EMP, which is consistent with their extremely long recombination lifetime (%7E10 ns). This contrasts with previous measurements on other magnetic quantum well systems for which the polarization of short-lived spatially direct EMP never saturates. Time-resolved photoluminescence measurements of excitons confined to CdSe self-assembled quantum dots (SAQDs) reveal the existence of two different exciton decay times: a short 450 ps lifetime and a much longer (> 4 ns) lifetime. While the emission resulting from the short lifetime excitons persists to room temperatures, the longlifetime component decreases in intensity with increasing temperature and is nearly completely gone by 60 K. Time-resolved spectra further reveal that the long lifetime component arises from spectrally sharp features (%7E200eV), while the rapid decay results from an underlying broad emission (%7E60 meV). Further analysis reveals that both states exhibit an activated behavior with activation energies that differ by over an order of magnitude for the two components. These interesting differences may reflect the complex nature of the electron and hole wave functions confined to these CdSe structures.
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 Theoretical Studies of Exciton Spin Dynamics Fine Structures and Optical Anisotropies of Semiconductor Quantum Dots written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultrafast Quantum Control of Exciton Dynamics in Semiconductor Quantum Dots written by Angela Gamouras 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 Dots written by Lucjan Jacak and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an overview of the theoretical background and experimental re sults in the rapidly developing field of semiconductor quantum dots - systems 8 6 of dimensions as small as 10- -10- m (quasi-zero-dimensional) that contain a small and controllable number (1-1000) of electrons. The electronic structure of quantum dots, including the energy quan tization of the single-particle states (due to spatial confinement) and the evolution of these (Fock-Darwin) states in an increasing external magnetic field, is described. The properties of many-electron systems confined in a dot are also studied. This includes the separation of the center-of-mass mo tion for the parabolic confining potential (and hence the insensitivity of the transitions under far infrared radiation to the Coulomb interactions and the number of particles - the generalized Kohn theorem) and the effects due to Coulomb interactions (formation of the incompressible magic states at high magnetic fields and their relation to composite jermions), and finally the spin-orbit interactions. In addition, the excitonic properties of quantum dots are discussed, including the energy levels and the spectral function of a single exciton, the relaxation of confined carriers, the metastable states and their effect on the photoluminescence spectrum, the interaction of an exciton with carriers, and exciton condensation. The theoretical part of this work, which is based largely on original re sults obtained by the authors, has been supplemented with descriptions of various methods of creating quantum-dot structures.
Download or read book Exciton Relaxation and Electron Transfer Dynamics of Semiconductor Quantum Dots written by Cunming Liu and published by . This book was released on 2015 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Quantum dots (QDs) exhibit unique electronic and optical properties arising from their three-dimensional confinement and strongly enhanced coulomb interactions. Developing a detailed understanding of their exciton relaxation dynamics is important not only for the sake of exploring the fundamental physics of quantum confinement processes, but also for their potential applications. Ultrafast transient absorption (TA) spectroscopy, which has been proven as a powerful tool to explore the relaxation dynamics of excitons, was employed to characterize the hot single/multiexciton relaxation dynamics at the first four exciton states 1Se-1S3/2 (1S), 1Se-2S3/2 (2S), 1Pe-1P3/2 (1P) and 1Se-2S1/2 (2SH) of CdSe/CdZnS QDs. We found all exciton states can accomplish their initialization in sub-ps timescales. And, the 1S single exciton mainly relaxes to surface trapping state with a lifetime of 0.90 ł 0.02 ns. A 74 ł 2 ps Auger recombination occurs to nonradiatively annihilate 1S multiexctions under higher pump fluence. We also observed for the first time that the 2S hot hole can relax via two possible pathways-intraband multiple phonon coupling (2S3/2-1P3/2 or 2S3/2-1S3/2) and the intrinsic defect trapping, with a lifetime of 7 ł 2 ps. Owing to the overlap between highly energetic 1P and 2SH exciton states, their probed dynamics both show the characteristics of 1P and 2SH exciton states. Surprisingly, an ultra-short component of 8 ł 1 ps, directly associated with the Auger recombination at the 1P exciton state, was discovered under higher pump fluence. After finishing the studies of exciton relaxation inside QDs, ultrafast TA spectroscopy was further applied to explore the electron transferring outside from QDs. By employing a novel photocatalytic system consisting of water-soluble CdSe QDs and Ni-dihydrolipoic acid (Ni-DHLA) catalyst, which has represented a robust photocatalysis of H2 from water, the photoinduced electron transfer (ET) dynamics between QDs and catalyst, one of most primary steps during H2 generation, was studied. We found that smaller bare CdSe QDs exhibit a better ET performance with an amplitude-weighted average lifetime of 69 ł 2 ps. And, nearly ~90% of TA signal in the presence of Ni-DHLA can be attributed to the ET process. CdS shelling on the bare CdSe QDs worsens the ET between QDs and Ni-DHLA catalysts. Under higher pump fluence, the ET performance with CdSe/CdS core-shell QDs is improved because of the Auger recombination in CdSe cores strongly suppressed by CdS shelling, which is contrary with bare CdSe QDs. These studies may supply potential ways to optimize the QDs sensitized photocatalytic systems for H2 production. Finally, by virtue of effective mass approximation (EMA) method and Marcus theory, the mechanism of ET between CdSe QDs and Ni-DHLA catalysts was clarified in theory. Additionally, photoluminescence (PL) quenching and time-resolved PL measurements were used to demonstrate that the main pathway for ET between QDs and Ni-DHLA catalysts is through dynamic collisions. As Ni-DHLA concentration increases, the static attachment between QDs and Ni-DHLA catalyst molecules can occur to further speed up the ET process from QDs to Ni-DHLA catalysts."--Pages vi-vii.
Download or read book Quantum Dots written by Peter A. Ling and published by Nova Publishers. This book was released on 2005 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.
Download or read book Single Quantum Dots written by Peter Michler and published by Springer Science & Business Media. This book was released on 2003-12-09 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Special focus is given to the optical and electronic properties of single quantum dots due to their potential applications in devices operating with single electrons and/or single photons. This includes quantum dots in electric and magnetic fields, cavity-quantum electrodynamics, nonclassical light generation, and coherent optical control of excitons.
Download or read book Quantum Optical Control of Spins and Excitons in Semiconductor Quantum Dots written by Pochung Chen and published by . This book was released on 2002 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Quantum Coherence Correlation and Decoherence in Semiconductor Nanostructures written by Toshihide Takagahara and published by Academic Press. This book was released on 2003-02-10 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanostructures are attracting a great deal of interest as the most promising device with which to implement quantum information processing and quantum computing. This book surveys the present status of nanofabrication techniques, near field spectroscopy and microscopy to assist the fabricated nanostructures. It will be essential reading for academic and industrial researchers in pure and applied physics, optics, semiconductors and microelectronics. - The first up-to-date review articles on various aspects on quantum coherence, correlation and decoherence in semiconductor nanostructures
