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Author: David Larousserie
Publisher:
ISBN:
Category :
Languages : fr
Pages : 168
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Author: David Larousserie
Publisher:
ISBN:
Category :
Languages : fr
Pages : 168
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Author: Alex Randall Hodges
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
We use time-resolved magneto-photoluminescence spectroscopy to study spin relaxation of excitons in a series of strained and unstrained ZnMnSe-based heterostructures. In an unstrained ZnMnSe epilayer, we find rapid spin relaxation, with a spin relaxation time of less than five picoseconds. We attribute this rapid spin relaxation to the complicated band structure: the various exciton spin bands intersect each other numerous times. The excitons can freely scatter between the spin bands, resulting in rapid spin relaxation. In contrast, we find extremely slow spin relaxation in a strained ZnMnSe/ZnFeSe multiple quantum well, with a spin relaxation time of greater than one nanosecond. Once excitons cool to the bottom of the band, very little spin relaxation occurs, and an extremely non-thermal exciton spin distribution persists throughout the lifetime of the exciton. In addition, we show that the dominant spin relaxation mechanism in this structure is LO-phonon emission during the momentum relaxation process, which occurs within 1 ps of the exciting laser pulse. We find similar results in two additional strained structures. For a strained ZnMnSe epilayer and a strained ZnMnSe/ZnSe multiple quantum well, we also see very slow spin relaxation, with spin relaxation times of greater than 1 ns. We conclude that this effect is due to the removal of the light hole - heavy hole valence band degeneracy by the lattice strain. This eliminates the band-mixing effects that lead to rapid spin relaxation in unstrained ZnMnSe-based heterostructures, thus resulting in extremely slow spin relaxation. We also find that the addition of a small fraction of cadmium to a strained quantum well strongly increases the spin relaxation rate. In a strained ZnCdMnSe/ZnSe quantum well, we see rapid spin relaxation, with a spin relaxation time of less than 5 ps, similar to that of the unstrained ZnMnSe epilayer. However, as in the other strained structures, the excitons spins never fully thermalize with the lattice. The spin relaxation, while initially rapid, is incomplete.
Author: Giovanni Agostini
Publisher: Newnes
ISBN: 044459549X
Category : Technology & Engineering
Languages : en
Pages : 829
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Book Description
Characterization of Semiconductor Heterostructures and Nanostructures is structured so that each chapter is devoted to a specific characterization technique used in the understanding of the properties (structural, physical, chemical, electrical etc..) of semiconductor quantum wells and superlattices. An additional chapter is devoted to ab initio modeling. The book has two basic aims. The first is educational, providing the basic concepts of each of the selected techniques with an approach understandable by advanced students in Physics, Chemistry, Material Science, Engineering, Nanotechnology. The second aim is to provide a selected set of examples from the recent literature of the TOP results obtained with the specific technique in understanding the properties of semiconductor heterostructures and nanostructures. Each chapter has this double structure: the first part devoted to explain the basic concepts, and the second to the discussion of the most peculiar and innovative examples. The topic of quantum wells, wires and dots should be seen as a pretext of applying top level characterization techniques in understanding the structural, electronic etc properties of matter at the nanometer (and even sub-nanometer) scale. In this respect it is an essential reference in the much broader, and extremely hot, field of Nanotechnology. Comprehensive collection of the most powerful characterization techniques for semiconductors heterostructures and nanostructures Most of the chapters are authored by scientists that are world-wide among the top-ten in publication ranking of the specific field Each chapter starts with a didactic introduction on the technique The second part of each chapters deals with a selection of top examples highlighting the power of the specific technique to analyse the properties of semiconductors heterostructures and nanostructures
Author: S. Sanguinetti
Publisher: Elsevier Inc. Chapters
ISBN: 012808345X
Category : Science
Languages : en
Pages : 75
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Book Description
Author: Carlo Lamberti
Publisher: Elsevier
ISBN:
Category : Architecture
Languages : en
Pages : 512
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Book Description
- Comprehensive collection of the most powerful characterization techniques for semiconductors heterostructures and nanostructures. - Most of the chapters are authored by scientists that are world wide among the top-ten in publication ranking of the specific field. - Each chapter starts with a didactic introduction on the technique. - The second part of each chapters deals with a selection of top examples highlighting the power of the specific technique to analyse the properties of semiconductors heterostructures and nanostructures.
Author: Mikhail I. Dyakonov
Publisher: Springer
ISBN: 3319654365
Category : Technology & Engineering
Languages : en
Pages : 546
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Book Description
This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.
Author: D.J. Lockwood
Publisher: Springer Science & Business Media
ISBN: 9401119120
Category : Science
Languages : en
Pages : 443
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Book Description
Remarkable advances in semiconductor growth and processing technologies continue to have a profound impact on condensed-matter physics and to stimulate the invention of novel optoelectronic effects. Intensive research on the behaviors of free carriers has been carried out in the two-dimensional systems of semiconductor heterostructures and in the one and zero-dimensional systems of nanostructures created by the state-of-the-art fabrication methods. These studies have uncovered unexpected quantum mechanical correlations that arise because of the combined effects of strong electron-electron interactions and wave function confinement associated with reduced dimensionality. The investigations of these phenomena are currently at the frontiers of condensed-matter physics. They include areas like the fractional quantum Hall effect, the dynamics of electrons on an ultra short (femtosecond) time scale, electron behavior in quantum wires and dots, and studies of electron tunneling phenomena in ultra small semiconductor structures. Optical techniques have made important contributions to these fields in recent years, but there has been no coherent review of this work until now. The book provides an overview of these recent developments that will be of interest to semiconductor materials scientists in university, government and industrial laboratories.
Author: Karl W. Böer
Publisher: Springer Nature
ISBN: 3031182863
Category : Technology & Engineering
Languages : en
Pages : 1408
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Book Description
This handbook gives a complete and detailed survey of the field of semiconductor physics. It addresses every fundamental principle, the most important research topics and results, as well as conventional and emerging new areas of application. Additionally it provides all essential reference material on crystalline bulk, low-dimensional, and amorphous semiconductors, including valuable data on their optical, transport, and dynamic properties. This updated and extended second edition includes essential coverage of rapidly advancing areas in semiconductor physics, such as topological insulators, quantum optics, magnetic nanostructures and spintronic systems. Richly illustrated and authored by a duo of internationally acclaimed experts in solar energy and semiconductor physics, this handbook delivers in-depth treatment of the field, reflecting a combined experience spanning several decades as both researchers and educators. Offering a unique perspective on many issues, Semiconductor Physics is an invaluable reference for physicists, materials scientists and engineers throughout academia and industry.
Author: Jagdeep Shah
Publisher: Springer Science & Business Media
ISBN: 366203770X
Category : Science
Languages : en
Pages : 536
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Book Description
Ultrafast spectroscopy of semiconductors and semiconductor nanostructures is currently one of the most exciting areas of research in condensed-matter physics. Remarkable recent progress in the generation of tunable femtosecond pulses has allowed direct investigation of the most fundamental dynamical processes in semiconductors. This second edition presents the most striking recent advances in the techniques of ultrashort pulse generation and ultrafast spectroscopy; it discusses the physics of relaxation, tunneling and transport dynamics in semiconductors and semiconductor nanostructures following excitation by femtosecond laser pulses.
Author: Guillaume Cassabois
Publisher:
ISBN:
Category :
Languages : fr
Pages : 183
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Book Description
NOUS AVONS ETUDIE LES MECANISMES RESPONSABLES DE LA PERTE DE COHERENCE DANS DES HETEROSTRUCTURES DE SEMICONDUCTEURS III-V PAR UNE TECHNIQUE LINEAIRE DE CORRELATION INTERFEROMETRIQUE DE LA DIFFUSION RAYLEIGH RESONANTE. CETTE TECHNIQUE REPOSE SUR L'EXCITATION D'UN ECHANTILLON PAR UNE PAIRE D'IMPULSIONS FEMTOSECONDES, COHERENTES, DE MEME INTENSITE ET DECALEES DANS LE TEMPS. LES INTERFERENCES ENTRE LES POLARISATIONS CREEES DANS L'ECHANTILLON PAR LA PAIRE D'IMPULSIONS PRODUISENT DES INTERFERENCES SUR L'EMISSION RESONANTE DU SYSTEME. LEUR CONTRASTE DECROIT AVEC LE RETARD ENTRE LES IMPULSIONS SUR UNE ECHELLE DE TEMPS DONNEE PAR LE TEMPS DE RELAXATION DE COHERENCE OU TEMPS DE DEPHASAGE T 2, DE L'ORDRE DE QUELQUES PICOSECONDES DANS LES HETEROSTRUCTURES DE SEMICONDUCTEURS. NOUS NOUS SOMMES D'ABORD INTERESSES A DES PUITS QUANTIQUES GAAS/AL XGA 1 - XAS PEU PROFONDS OU LA CONCENTRATION EN ALUMINIUM DANS L'ALLIAGE DE BARRIERE VARIE DE 18 A 1,5%. DANS CES PUITS QUANTIQUES, LES EXCITONS SONT DANS UN REGIME DE CONFINEMENT FAIBLE INTERMEDIAIRE ENTRE LES PUITS PROFONDS (2D) ET LE MATERIAU MASSIF (3D). GRACE A DES EXPERIENCES REALISEES POUR DIFFERENTES TEMPERATURES DE L'ECHANTILLON, NOUS AVONS ETUDIE L'INFLUENCE DE LA TRANSITION 2D-3D SUR LES MECANISMES DE DEPHASAGE PAR PHONONS. POUR LES PHONONS ACOUSTIQUES, NOUS METTONS EN EVIDENCE UNE TRANSITION MOLLE ALORS QUE POUR LES PHONONS OPTIQUES, NOUS OBSERVONS UNE RESONANCE DE COUPLAGE POUR LE PUITS X=3,3% OU LES EXCITONS DU PUITS ET DE LA BARRIERE SONT DISTANTS D'UN PHONON OPTIQUE. NOUS AVONS PAR AILLEURS ETUDIE UNE MICROCAVITE DE SEMICONDUCTEURS EN COUPLAGE FORT. DANS CETTE HETEROSTRUCTURE, LES ETATS PROPRES NE SONT PLUS DES EXCITONS MAIS DES ETATS MIXTES EXCITON-PHOTON, LES POLARITONS DE CAVITE. DANS CE SYSTEME, LA RELAXATION DE COHERENCE EST GOUVERNEE PAR DES MECANISMES DE DEPHASAGE DE TYPES TRES DIFFERENTS POUR LES COMPOSANTES EXCITON ET PHOTON, RESPECTIVEMENT. TOUT D'ABORD, PAR DES ETUDES A BASSE TEMPERATURE EN FONCTION DU DESACCORD EN ENERGIE ENTRE LES MODES EXCITON ET PHOTON, NOUS METTONS EN EVIDENCE LES SPECIFICITES DE LA RELAXATION DE COHERENCE DES POLARITONS DE CAVITE. NOUS AVONS DEVELOPPE UN CALCUL DE LA DIFFUSION RAYLEIGH RESONANTE D'UNE MICROCAVITE A PARTIR D'UN MODELE SEMI-CLASSIQUE DE DISPERSION LINEAIRE ET NOUS OBTENONS UN EXCELLENT ACCORD THEORIE/EXPERIENCE. PAR AILLEURS, PAR DES ETUDES EN FONCTION DE LA TEMPERATURE, NOUS AVONS EXAMINE LE DEPHASAGE DES POLARITONS ASSISTE PAR PHONONS ACOUSTIQUES. NOUS METTONS EN EVIDENCE LES LIMITES D'UN MODELE SEMI-CLASSIQUE POUR DECRIRE LA RELAXATION DE COHERENCE EN FONCTION DE LA TEMPERATURE ET NOUS REPRODUISONS NOS DONNEES EXPERIMENTALES A L'AIDE D'UN MODELE QUANTIQUE DE POLARITONS.
