Relevant bibliographies by topics / Exciton wannier

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Academic literature on the topic 'Exciton wannier'

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Published: 4 June 2021
Last updated: 10 February 2022

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Journal articles on the topic "Exciton wannier"

1

Gunlycke, Daniel, and Frank Tseng. "Triangular lattice exciton model." Physical Chemistry Chemical Physics 18, no. 12 (2016): 8579–86. http://dx.doi.org/10.1039/c6cp00205f.

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2

Kayanuma, Y. "Wannier exciton in microcrystals." Solid State Communications 59, no. 6 (August 1986): 405–8. http://dx.doi.org/10.1016/0038-1098(86)90573-9.

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3

Семина, М. А. "Тонкая структура ридберговских экситонов в закиси меди." Физика твердого тела 60, no. 8 (2018): 1515. http://dx.doi.org/10.21883/ftt.2018.08.46238.05gr.

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AbstractIn 1952, E.F. Gross and N.A. Karryev discovered excitons of big radius also called the Wannier–Mott excitons. Their energy spectrum, response to external electric and magnetic fields, and also elastic deformations of a crystal were extensively studied in the 1960s–1970s. The second wave of interest to excitons in Cu_2O crystals appeared comparatively recent, in 2014, after the “giant” highly excited exciton states had been observed in this material. A theoretical description of highly excited exciton states needs, as a rule, new approaches, because, for such states, a deviation from the exactly solved hydrogen-like model becomes substantial and a numerical solution of the Schrödinger equation with allowance made for the features of the crystal energy band structure becomes extremely resource consuming. This report is a brief review of recent theoretical and experimental studies of the fine structure of the exciton energy spectrum in copper protoxide.
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4

Mavroyannis, Constantine. "Charge transfer electron–exciton complexes in single crystals." Canadian Journal of Chemistry 63, no. 7 (July 1, 1985): 1345–48. http://dx.doi.org/10.1139/v85-229.

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We have considered the excitation spectrum arising from the coherent electron–exciton pairing in crystals at low temperatures. For the pairing processes, three different types of excitons have been considered: Frenkel excitons (tightly bound), Wannier–Mott excitons (loosely bound), and excitons of the intermediate binding. Expressions for the gap functions and transition temperatures at which metal-to-nonmetal phase transitions occur have been derived and discussed for each type of pairing. In the electron pairing with the intermediate exciton, the dispersion relations which determine the exciton and the electron–exciton modes are solved numerically and the derived results are graphically presented. The physical picture for the electron–exciton coupled modes is analogous to that for polaritons and magnon–phonon modes in crystals.
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5

HE, MENG-DONG, LING-LING WANG, WEI-QING HUANG, BING-SOU ZOU, and KE-QIU CHEN. "LOCALIZED WANNIER EXCITON IN DEFECT LAYER EMBEDDED BETWEEN TWO SEMI-INFINITE SUPERLATTICES." International Journal of Modern Physics B 24, no. 18 (July 20, 2010): 3501–11. http://dx.doi.org/10.1142/s0217979210052520.

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The characteristics of the localized Wannier exciton in defect layer (GaAs) embedded between two semi-infinite superlattices (GaAs/Al x Ga 1-x As ) are investigated theoretically using a variational approach. It can be clearly seen the exciton changes in character between three- and quasi-two-dimensional states from the variation of exciton binding energy, in-plane radius, and probability in the superlattices (SLs) growth direction. We find that the extensions of exciton in directions both parallel and perpendicular to the interface of SLs almost approach their minimums as the exciton binding energy reaches peak value at a certain defect width. Our results show that the binding energy of the ground exciton state is sensitive to Al concentration x in Al x Ga 1-x As and thicknesses of the constituent layers. The comparison between excitonic behavior in structural defect SLs and single quantum well is made.
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6

Postorino, Sara, Jianbo Sun, Saskia Fiedler, Laurent O. Lee Cheong Lem, Maurizia Palummo, and Luca Camilli. "Interlayer Bound Wannier Excitons in Germanium Sulfide." Materials 13, no. 16 (August 12, 2020): 3568. http://dx.doi.org/10.3390/ma13163568.

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We report a cathodoluminescence (CL) study of layered germanium sulfide (GeS) where we observe a sharp emission peak from flakes covered with a thin hexagonal boron nitride film. GeS is a material that has recently attracted considerable interest due to its emission in the visible region and its strong anisotropy. The measured CL peak is at ~1.69 eV for samples ranging in thickness from 97 nm to 45 nm, where quantum-confinement effects can be excluded. By performing ab initio ground- and excited-state simulations for the bulk compound, we show that the measured optical peak can be unambiguously explained by radiative recombination of the first free bright bound exciton, which is due to a mixing of direct transitions near the Γ-point of the Brillouin Zone and it is associated to a very large optical anisotropy. The analysis of the corresponding excitonic wave function shows a Wannier–Mott interlayer character, being spread not only in-plane but also out-of-plane.
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7

Khurgin, Jacob B. "Pliable polaritons: Wannier exciton-plasmon coupling in metal-semiconductor structures." Nanophotonics 8, no. 4 (November 20, 2018): 629–39. http://dx.doi.org/10.1515/nanoph-2018-0166.

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AbstractPlasmonic structures are known to support the modes with sub-wavelength volumes in which the field/matter interactions are greatly enhanced. Coupling between the molecular excitations and plasmons leading to the formation of “plexcitons” has been investigated for a number of organic molecules. However, plasmon-exciton coupling in metal/semiconductor structures has not experienced the same degree of attention. In this work, we show that the “very strong coupling” regime in which the Rabi energy exceeds the exciton binding energy is attainable in semiconductor-cladded plasmonic nanoparticles and leads to the formation of Wannier exciton-plasmon polariton (WEPP), which is bound to the metal nanoparticle and characterized by dramatically smaller (by a factor of a few) excitonic radius and correspondingly higher ionization energy. This higher ionization energy, which exceeding approaches 100 meV for the CdS/Ag structures, may make room-temperature Bose-Einstein condensation and polariton lasing in plasmonic/semiconductor structures possible.
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8

GÖPPERT, M., R. BECKER, C. MAIER, M. JÖRGER, A. JOLK, and C. KLINGSHIRN. "INFRARED ABSORPTION BY EXCITONS IN CUPROUS OXIDE." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3615–18. http://dx.doi.org/10.1142/s0217979201008275.

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We report on the first observation of the 1s to 2p exciton transition in a direct gap semiconductor. Cuprous oxide is well known for its excitonic features which provide a model case for the theory of Wannier excitons. In our pump-probe experiment we measured the infrared transmission of cuprous oxide with the without Ar +-laser illumination. The observed photo-induced absorption line in the differential transmission spectra at 126 meV is assigned to the excitonic transition from 1s to 2p exciton levels i.e. to the analog of the Lyman series in atomic hydrogen. From the dependence of the integrated photo-induced absorption on the pump laser intensity we determine the lifetime of the paraexciton τ p ≈0.3 ms. We also studied the influence of the pump laser on the phonon absorption band in the mid-infrared. Its observed shift to lower energies with increasing pump laser intensity can be explained by heating of the samples.
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9

FAN, HONG-YI, HUI ZOU, YUE FAN, and QIU-YU LIU. "ENERGY SPECTRUM OF MOTT–WANNIER EXCITON STUDIED BY VIRTUE OF THE EXCITON ENTANGLED STATE REPRESENTATION INSTEAD OF K·P PERTURBATION THEORY." Modern Physics Letters B 19, no. 13n14 (June 20, 2005): 637–42. http://dx.doi.org/10.1142/s0217984905008645.

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We introduce the exciton entangled state. We show that the energy spectrum of Mott–Wannier exciton can be exactly derived by virtue of the entangled state representation. In contrast to the K · P perturbation theory this new approach seems non-perturbative, direct and exact.
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10

Ridene, Rym, Nouha Mastrour, Dhouha Gamra, and Habib Bouchriha. "Energetic behavior of excitons in hybrid organic–inorganic parabolic quantum dots and its electric field dependence." International Journal of Modern Physics B 29, no. 30 (November 18, 2015): 1550211. http://dx.doi.org/10.1142/s0217979215502112.

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In this paper, dispersion energies of Wannier–Mott, Frenkel and mixed exciton formation at the interface in nanocomposite organic–inorganic parabolic quantum dots are investigated theoretically taking account of the interaction between the two excitonic states and electric field effect. Illustration is given for three nanocomposites highly studied experimentally, such as organic P3HT combined respectively with inorganic (CdSe, ZnSe, ZnO) parabolic quantum dots. It is shown that the parameter governing the interaction between the individual exciton states depends on the inorganic quantum dot and can be controlled by the electric field. The results are consistent with the available experimental data.
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Dissertations / Theses on the topic "Exciton wannier"

1

Piccioli, Norbert. "Constantes optiques du seleniure de gallium : variation avec la temperature et bistabilite optique induite par effet thermique." Paris 6, 1987. http://www.theses.fr/1987PA066196.

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Verification du modele d'elliot pour le cas d'une transition directe avec interaction electron-trou. Le modele a ete modifie pour tenir compte de l'anisotropie et de l'interaction avec les vibrations du reseau. L'analyse, effectuee entre 2 et 500 k, a permis de suivre l'evolution des parametres excitoniques et de la structure de bande avec la temperature. La forme des raies excitoniques avec lorentzienne asymetrique a ete predite. A partir de la, la nature de l'exciton direct et de l'interaction exciton-phonon ont pu etre deduites
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2

Medeiros, F?bio Ferreira de. "Polaritons de exciton em super-redes semicondutoras." Universidade Federal do Rio Grande do Norte, 2004. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16644.

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Made available in DSpace on 2014-12-17T15:15:02Z (GMT). No. of bitstreams: 1 FabioFM.pdf: 1459636 bytes, checksum: 4f2bb557c6a5bddb80e46f325bd5b4dd (MD5) Previous issue date: 2004-12-03
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In this work we study the spectrum (bulk and surface modes) of exciton-polaritons in infinite and semi-infinite binary superlattices (such as, ???ABABA???), where the semiconductor medium (A), whose dielectric function depends on the frequency and the wavevector, alternating with a standard dielectric medium B. Here the medium A will be modeled by a nitride III-V semiconductor whose main characteristic is a wide-direct energy gap Eg. In particular, we consider the numerical values of gallium nitride (GaN) with a crystal structure wurtzite type. The transfer-matrix formalism is used to find the exciton-polariton dispersion relation. The results are obtained for both s (TE mode: transverse electric) and p (TM mode: transverse magnetic) polarizations, using three diferent kind of additional boundary conditions (ABC1, 2 e 3) besides the standard Maxwell's boundary conditions. Moreover, we investigate the behavior of the exciton-polariton modes for diferent ratios of the thickness of the two alternating materials forming the superlattice. The spectrums shows a confinement of the exciton-polariton modes due to the geometry of the superlattice. The method of Attenuated Total Reflection (ATR) and Raman scattering are the most adequate for probing this excitations
Neste trabalho estudamos o espectro (modos de volume e de superf?cie) dos polaritons de exciton em uma super-rede bin?ria infinita e semi-infinita (tal como, ???ABABA???), onde um meio semicondutor (A), cuja fun??o diel?trica depende da frequ?ncia e do vetor de onda, alterna-se com um diel?trico comum (B). Aqui, o meio A ser? modelado por um semicondutor da fam?lia dos nitretos (semicondutor III-V) que tem como caracter?stica principal um gap de energia (Eg) direto e largo. Em particular, consideramos os valores num?ricos para o nitreto de g?lio (GaN) com uma estrutura cristalina tipo wurtzite. A t?cnica da matriz de transfer?ncia ? utilizada para encontrarmos a rela??o de dispers?o do polariton de exciton. Os resultados s?o obtidos para os modos de polariza??o s (ou modo TE: transversal el?trico) e p (ou modo TM: transversal magn?tico), usando tr?s diferentes condi??es de contorno adicionais (ABC1, 2 e 3), mais as condi??es de contorno padr?es de Maxwell. Al?m disso, investigamos o comportamento dos modos do polariton de exciton para diferentes raz?es entre as espessuras das camadas dos dois materiais que comp?em a super-rede Os espectros encontrados evidenciam um comportamento de confinamento dos polaritons de exciton devido ?s geometrias empregadas. As t?cnicas experimentais ATR ("Attenuated Total Reflection") e o espalhamento Raman s?o as mais adequadas para a caracteriza??o dessas excita??es
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3

Rosam, Ben. "Intraband Dynamics in the Optically Excited Wannier-Stark Ladder Spectrum of Semiconductor Superlattices." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1122486920194-75406.

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In semiconductor superlattices, the carrier band structure can be tailored by the proper choice of their geometry. Therefore, superlattices are a model system for the study of coherent high-field transport phenomena in a periodic potential with applied static electric field. This thesis is structured in two parts. I. Zener Tunneling in Semiconductor Superlattices. In this work,semiconductor superlattices with shallow barriers and narrow band gaps were employed to investigate the Zener breakdown. In these samples, tunneling in the electron Wannier-Stark ladder spectrum is addressed as coupling of the electron states of a single bound below-barrier band to the states of the above-barrier spectrum. The field-dependent evolution of the Wannier-Stark ladder states was traced in the optical interband spectrum. Superlattices with different geometries were employed, to clarify the influence of the particular miniband structure on the Zener tunneling behavior. It was shown that in the presence of Zener tunneling, the Wannier-Stark ladder picture becomes invalid. Tunneling is demonstrated to lead to a field-induced delocalization of Wannier-Stark ladder states. In addition, the coherent polarization lifetime was analyzed as a measure of the tunneling probability. II. Terahertz Emission of Exciton Wave Packets in Semiconductor Superlattices. By means of Terahertz spectroscopy, the coherent intraband dynamics of exciton wave packets in biased superlattices after the selective ultrafast excitation of the Wannier-Stark ladder spectrum was investigated. The dynamics of Bloch oscillations was investigated under broadband excitation. It is demonstrated, that the Bloch oscillation amplitude can be controlled by altering the pump pulse energy. The xperimental results can only be explained in a full exciton picture, incorporating bound 1s exciton states and the associated exciton in-plane continuum. The intraband dipole of single Wannier-Stark ladder excitons was measured by detecting the Terhartz response after excitation of the Wannier-Stark ladder with a spectrally narrow rectangular pump pulse. In addition, experiments revealed a previously unknown mechanism for the generation of Bloch oscillating exciton wave packets. This was demonstrated for an incident pump spectrum which was too narrow to excite a superposition of Wannier-Stark ladder states. The effect is based on the sudden, non-adiabatic, change in the net dc internal field due to creation of electron-hole pairs with permanent dipole moments. The non-adiabatic generation of Bloch oscillations is a highly nonlinear effect mediated by strong exciton-exciton interactions.The central role that play exciton-exciton interactions in the intraband dynamics became especially evident when the Wannier-Stark ladder was selectively excited by two spectrally narrow laser lines. The experiments demonstrated a resonant enhancement of the intraband transition matrix element when 1s exciton wavepackets are excited
In Halbleiter-Übergittern kann die Bandstruktur von Ladungsträgern durch die geeignete Wahl der Geometrie eingestellt werden. Deshalb sind Halbleiter-Übergitter ein Modellsystem für Untersuchungen des kohärenten Ladungstransportes im periodischen Potential bei hohen, statischen, elektrischen Feldern. Diese Doktorarbeit ist in zwei Teile untergliedert. I. Zener-Tunneln in Halbleiter-Übergittern In dieser Arbeit werden Halbleiter-Übergitter mit flachen Barrieren und schmalen Bandlücken eingesetzt, um den Effekt des Zener-Durchbruchs zu untersuchen. In diesen Strukturen wird das Zener-Tunneln im Elektronen-Spektrum der Wannier-Stark-Leiter adressiert. Dabei handelt es sich um die Kopplung von Elektronen-Zuständen eines einzelnen Minibandes unterhalb der Potentialbarriere des Quantentopfes mit Zuständen oberhalb der Barriere. Die Feldabhängigkeit der Wannier-Stark-Leiter-Zustände wurde im optischen Interband-Spektrum detektiert. Übergitter mit unterschiedlichen Geometrien wurden untersucht, um den Einfluss der spezifischen Miniband-Struktur auf die Charakteristiken des Zener-Tunnelns aufzuklären. Es wurde gezeigt, dass im Regime des Zener-Tunnelns das Wannier-Stark-Leiter-Bild nicht mehr gültig ist. Dabei wird demonstriert, dass Tunneln zu einer feldabhängigen Delokalisierung der Wannier-Stark-Leiter-Zustände führt. Außerdem wird die Kohärenz-Lebensdauer der Polarisation analysiert. Sie bildet die Tunneln-Wahrscheinlichkeit ab. II. Terahertz Emission von Exzitonen-Wellen-Paketen in Halbleiter-Übergittern Mit Hilfe von Terahertz-Spektroskopie wurde die kohärente Intraband-Dynamik von Exzitonen-Wellen-Paketen in vorgespannten Halbleiter-Übergittern nach der selektiven, ultrakurzen Anregung des Wannier-Stark-Leiter-Spektrums untersucht. Die Dynamik von Bloch-Oszillatonen wurde durch spektral breitbandiger Anregung detektiert. Es wird gezeigt, dass die Amplitude von Bloch-Oszillationen durch die Änderung der Energie des Anrege-Pulses beeinflusst werden kann. Die experimentellen Resultate können nur in einem ganzheitlichen Exzitonenbild erklärt werden. Es umfaßt die gebundenen 1s-Exziton-Zustände und das zugehörige Exzitonen-Kontinuum in der Quantentopfschicht. Der Intraband-Dipol einzelner Wannier-Stark-Leiter-Exzitonen wurde durch die Detektion der Terahertz-Antwort auf die Anregung der Wannier-Stark-Leiter mit einem spektral schmalen Anrege-Puls vermessen. Außerdem wird in den Experimenten ein zuvor ungekannten Mechanismus der Anregung von bloch-oszillierenden Wellen-Paketen beobachtet. Dieser Effekt wird für ein eingestrahltes Anrege-Spektrum, welches spektral zu schmal für die Anregung einer Überlagerung von Wannier-Stark-Leiter-Zuständen ist, demonstriert. Der Mechanismus basiert auf die unmittelbare, nicht-adiabatische Änderung des effektiven, internen, statischen Feldes auf Grund der Anregung von Elektron-Loch-Paaren mit permanentem Dipolmoment. Die nicht-adiabatische Anregung von Bloch-Oszillationen ist ein hoch nicht-linearer Effekt, der durch starke Exziton-Exziton Wechselwirkung vermittelt wird. Die zentrale Rolle, die die Exziton-Exziton Wechselwirkung in der Intraband-Dynamik spielt, wurde besonders deutlich bei der selektiven Anregung der Wannier-Stark-Leiter durch zwei spekral schmale Laserlinien. Die Experimente demonstrieren eine resonante Überhöhung des Intraband-Übergangs-Matrix-Elements, wenn 1s-Exziton-Wellen-Pakete angeregt werden
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4

Rosam, Ben. "Intraband Dynamics in the Optically Excited Wannier-Stark Ladder Spectrum of Semiconductor Superlattices." Doctoral thesis, Technische Universität Dresden, 2004. https://tud.qucosa.de/id/qucosa%3A24547.

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In semiconductor superlattices, the carrier band structure can be tailored by the proper choice of their geometry. Therefore, superlattices are a model system for the study of coherent high-field transport phenomena in a periodic potential with applied static electric field. This thesis is structured in two parts. I. Zener Tunneling in Semiconductor Superlattices. In this work,semiconductor superlattices with shallow barriers and narrow band gaps were employed to investigate the Zener breakdown. In these samples, tunneling in the electron Wannier-Stark ladder spectrum is addressed as coupling of the electron states of a single bound below-barrier band to the states of the above-barrier spectrum. The field-dependent evolution of the Wannier-Stark ladder states was traced in the optical interband spectrum. Superlattices with different geometries were employed, to clarify the influence of the particular miniband structure on the Zener tunneling behavior. It was shown that in the presence of Zener tunneling, the Wannier-Stark ladder picture becomes invalid. Tunneling is demonstrated to lead to a field-induced delocalization of Wannier-Stark ladder states. In addition, the coherent polarization lifetime was analyzed as a measure of the tunneling probability. II. Terahertz Emission of Exciton Wave Packets in Semiconductor Superlattices. By means of Terahertz spectroscopy, the coherent intraband dynamics of exciton wave packets in biased superlattices after the selective ultrafast excitation of the Wannier-Stark ladder spectrum was investigated. The dynamics of Bloch oscillations was investigated under broadband excitation. It is demonstrated, that the Bloch oscillation amplitude can be controlled by altering the pump pulse energy. The xperimental results can only be explained in a full exciton picture, incorporating bound 1s exciton states and the associated exciton in-plane continuum. The intraband dipole of single Wannier-Stark ladder excitons was measured by detecting the Terhartz response after excitation of the Wannier-Stark ladder with a spectrally narrow rectangular pump pulse. In addition, experiments revealed a previously unknown mechanism for the generation of Bloch oscillating exciton wave packets. This was demonstrated for an incident pump spectrum which was too narrow to excite a superposition of Wannier-Stark ladder states. The effect is based on the sudden, non-adiabatic, change in the net dc internal field due to creation of electron-hole pairs with permanent dipole moments. The non-adiabatic generation of Bloch oscillations is a highly nonlinear effect mediated by strong exciton-exciton interactions.The central role that play exciton-exciton interactions in the intraband dynamics became especially evident when the Wannier-Stark ladder was selectively excited by two spectrally narrow laser lines. The experiments demonstrated a resonant enhancement of the intraband transition matrix element when 1s exciton wavepackets are excited.
In Halbleiter-Übergittern kann die Bandstruktur von Ladungsträgern durch die geeignete Wahl der Geometrie eingestellt werden. Deshalb sind Halbleiter-Übergitter ein Modellsystem für Untersuchungen des kohärenten Ladungstransportes im periodischen Potential bei hohen, statischen, elektrischen Feldern. Diese Doktorarbeit ist in zwei Teile untergliedert. I. Zener-Tunneln in Halbleiter-Übergittern In dieser Arbeit werden Halbleiter-Übergitter mit flachen Barrieren und schmalen Bandlücken eingesetzt, um den Effekt des Zener-Durchbruchs zu untersuchen. In diesen Strukturen wird das Zener-Tunneln im Elektronen-Spektrum der Wannier-Stark-Leiter adressiert. Dabei handelt es sich um die Kopplung von Elektronen-Zuständen eines einzelnen Minibandes unterhalb der Potentialbarriere des Quantentopfes mit Zuständen oberhalb der Barriere. Die Feldabhängigkeit der Wannier-Stark-Leiter-Zustände wurde im optischen Interband-Spektrum detektiert. Übergitter mit unterschiedlichen Geometrien wurden untersucht, um den Einfluss der spezifischen Miniband-Struktur auf die Charakteristiken des Zener-Tunnelns aufzuklären. Es wurde gezeigt, dass im Regime des Zener-Tunnelns das Wannier-Stark-Leiter-Bild nicht mehr gültig ist. Dabei wird demonstriert, dass Tunneln zu einer feldabhängigen Delokalisierung der Wannier-Stark-Leiter-Zustände führt. Außerdem wird die Kohärenz-Lebensdauer der Polarisation analysiert. Sie bildet die Tunneln-Wahrscheinlichkeit ab. II. Terahertz Emission von Exzitonen-Wellen-Paketen in Halbleiter-Übergittern Mit Hilfe von Terahertz-Spektroskopie wurde die kohärente Intraband-Dynamik von Exzitonen-Wellen-Paketen in vorgespannten Halbleiter-Übergittern nach der selektiven, ultrakurzen Anregung des Wannier-Stark-Leiter-Spektrums untersucht. Die Dynamik von Bloch-Oszillatonen wurde durch spektral breitbandiger Anregung detektiert. Es wird gezeigt, dass die Amplitude von Bloch-Oszillationen durch die Änderung der Energie des Anrege-Pulses beeinflusst werden kann. Die experimentellen Resultate können nur in einem ganzheitlichen Exzitonenbild erklärt werden. Es umfaßt die gebundenen 1s-Exziton-Zustände und das zugehörige Exzitonen-Kontinuum in der Quantentopfschicht. Der Intraband-Dipol einzelner Wannier-Stark-Leiter-Exzitonen wurde durch die Detektion der Terahertz-Antwort auf die Anregung der Wannier-Stark-Leiter mit einem spektral schmalen Anrege-Puls vermessen. Außerdem wird in den Experimenten ein zuvor ungekannten Mechanismus der Anregung von bloch-oszillierenden Wellen-Paketen beobachtet. Dieser Effekt wird für ein eingestrahltes Anrege-Spektrum, welches spektral zu schmal für die Anregung einer Überlagerung von Wannier-Stark-Leiter-Zuständen ist, demonstriert. Der Mechanismus basiert auf die unmittelbare, nicht-adiabatische Änderung des effektiven, internen, statischen Feldes auf Grund der Anregung von Elektron-Loch-Paaren mit permanentem Dipolmoment. Die nicht-adiabatische Anregung von Bloch-Oszillationen ist ein hoch nicht-linearer Effekt, der durch starke Exziton-Exziton Wechselwirkung vermittelt wird. Die zentrale Rolle, die die Exziton-Exziton Wechselwirkung in der Intraband-Dynamik spielt, wurde besonders deutlich bei der selektiven Anregung der Wannier-Stark-Leiter durch zwei spekral schmale Laserlinien. Die Experimente demonstrieren eine resonante Überhöhung des Intraband-Übergangs-Matrix-Elements, wenn 1s-Exziton-Wellen-Pakete angeregt werden.
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5

Loughan, Arlene M. "Above and below the Wannier threshold." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268183.

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6

Bianchi, Francesco. "Energy Transfer in Organic-Inorganic Semiconductor Structures." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19286.

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In HIOS-Strukturen, die auf einem Quantengraben und einer angrenzenden organischen Deckschicht basieren, wurde eine effiziente Umwandlung von Wannier-Exzitonen in Frenkel-Exzitonen mittels resonantem Förster Energietransfer (FRET) demonstriert. Das hier verwendete Design besteht aus einem spiro-annulierten Quarter-phenyl (L4P-SP3), das auf einen ZnO-Quantengraben (SQW) aufgewachsen wurde, um inkohärente Kopplung zu erreichen. Mittels optischer Spektroskopie haben wir demonstriert, dass diese hybriden Strukturen Energietransfer vom SQW zu den organischen Molekülen mit einer Effizienz von bis zu 77% zeigen. Allerdings zeigen UPS-Messungen eine typ-II-artige Energieniveau-Anpassung zwischen ZnO und der molekularen Schicht, die zu einem sehr effizienten Ladungstrennungsvorgang (ηCT=0.9) führt, der die molekulare Emission unterdrückt. Die erste beruht auf einer schnellen und hocheffizienten Energietransfer-Kaskade: nach der ersten Transferstufe wird die Anregungsenergie von der hybriden Grenzfläche weggeleitet, indem eine zweite Energietransferstufe eingeführt wird, bevor die Dissoziation der Exzitonen an der Grenzfläche statt-finden kann. Wir verwenden Sexiphenyl, L6P als endgültigen Akzeptor. In solch einer Struktur können wir eine Wiederherstellung der molekularen Emission um einen Faktor acht demonstrieren und zeigen, dass der Energietransferprozess zwischen L4P-SP3 und L6P den Ladungstrennungsprozess fast vollständig überholt. Als andere Option haben wir die Energieniveaus angepasst, indem eine organometallische Donor-Monolage [RuCp*mes] ergänzt wird. Diese Zwischenschicht senkt die Austrittsarbeit von ZnO deutlich ab und führt so zu einer Anpassung der Niveaus zwischen die zwei Halbleiter. Während die Effizienz des Energietransfers unverändert bleibt, steigen die Emission von L4P-SP3 sowie die Lebenszeit der molekularen Photoluminescenz um einen Faktor sieben verglichen mit entsprechenden Strukturen ohne Zwischenlage.
In HIOS structures based on a quantum well and an adjacent organic overlayer, efficient conversion of Wannier excitons into Frenkel excitons via Förster-type resonant energy transfer (FRET) has been demonstrated. The design here in use consists of a spiro-annulated ladder-type quarter-phenyl (L4P-SP3), deposited on ZnO-based single quantum wells (SQW) to obtain incoherent electronic coupling. The SQWs we use are grown with extremely thin (2 nm) capping layer. With photoluminescence excitation and time-resolved spectroscopy, we demonstrate that these hybrid structures exhibit energy transfer from the inorganic material to the organic molecules with an efficiency up to 77%. However, UPS measurements show a type-II energy level alignment between ZnO and the molecular layer, resulting in a very efficient charge separation process (ηCT=0.9) that suppresses the molecular emission. The first idea relies on a fast and highly efficient cascade FRET: following the primary transfer step from the QW, the excitation is conveyed away from the hybrid interface by a secondary transfer-step within the organic layer. As final acceptor we select ladder-type sexiphenyl (L6P). In such a structure, we demonstrate a recovery of the molecular emission by a factor eight, showing that the intermolecular FRET outpaced almost entirely the charge separation process. As alternative option, we tune the energy levels at the interface by introducing an organometallic donor monolayer [RuCp*mes]. The interlayer reduces substantially the ZnO work function, aligning the frontier levels of the inorganic and organic semiconductor. Optical experiments show the benefits of the interlayer: while the FRET efficiency is unaffected, the L4P-SP3 emission and its photoluminescence lifetime increase by a factor of seven, when compared to the same structure without interlayer.
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Yang, L. "Self-consistent driven block oscillatons in excitonic Wannier-Stark ladder." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60873.pdf.

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Chen, Yueh-Nan, and 陳岳男. "Superradiance of Wannier Excitons in Microstructures." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/38204035495014635216.

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博士
國立交通大學
電子物理系
90
In this dissertation, we consider the superradiant decay rate and renormalized frequency shift of Wannier excitons in the quantum well, quantum wire, and quantum ring. The crossover behaviors from 3D to 2D, 2D to 1D, and 1D to 0D are also studied. The density of the excitons is assumed to be small so that one can neglect nonbosonic commutation relation of excitons. In semiconductor quantum wells, the superradiant decay rate and renormalized frequency shift are found to show oscillatory dependence on well widths. The crossover from the superradiant exciton to bulk polariton is also examined. In the case of quantum wires, it is shown that the dark-mode exciton can be verified experimentally when the wires are embedded in a planar microcavity. It is also found that the decay rate is greatly enhanced as the cavity length is equal to the multiple half-wavelengths of the emitted photon. Similar to its decay rate counterpart, the frequency shift also shows discontinuities at the resonant modes. Moreover, we have also considered the superradiant decay of a quantum ring Wannier exciton inside the planar microcavity. It is found the Aharonov-Bohm oscillations might be observable easily at some resonant peaks. On the other hand, we have also considered a quantum dot inside a microcavity. Instead of optical measurements, we point out that the Purcell effects can be verified electrically by measuring the current through a two-level quantum dot.
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Lin, Wei-Cheng, and 林緯政. "Application of Wannier Functions on the dynamics of strongly bounded excitons." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/91906417603560189269.

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碩士
淡江大學
物理學系碩士班
98
A first-principles Wannier-function method is proposed to explore the propagation of the strongly bound Frenkel exciton in Alkali Halides ( LiF, LiCl, LiBr, NaF, NaCl, and NaBr). This study find strongly angular dependence of the excitons by means of a direct product of the Fourier transform of the local particle-hole wave functions. This result can straightforward explain the angular resolved inelastic x-ray scattering experiment. Furthermore, in order to solve response function of strongly interacting system within the linear response scheme more effectively, a new approach is proposed by formulating the “effective two-particle kinetic kernel (T) ” which contains all the mobility information of excitons.
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Rosam, Ben [Verfasser]. "Intraband dynamics in the optically excited Wannier-Stark ladder spectrum of semiconductor superlattices / vorgelegt von Ben Rosam." 2005. http://d-nb.info/976475251/34.

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Book chapters on the topic "Exciton wannier"

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Jaziri, S. "Electric Field Effect on Frenkel-Wannier-Mott Exciton States in Organic-Inorganic Semiconductor Quantum Wells." In Science and Technology of Polymers and Advanced Materials, 251–58. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4899-0112-5_23.

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Schultheis, L., J. Kuhl, A. Honold, and C. W. Tu. "Optical Dephasing of Wannier Excitons in GaAs." In Springer Proceedings in Physics, 50–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73291-1_6.

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Schultheis, L., J. Kuhl, A. Honold, and C. W. Tu. "Picosecond Relaxation of Nonthermal Wannier Excitons in GaAs." In Springer Series in Chemical Physics, 201–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82918-5_54.

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Schultheis, L., K. Köhler, and C. W. Tu. "Wannier Excitons at GaAs Surfaces and in Thin GaAs Layers." In Springer Proceedings in Physics, 110–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-73291-1_14.

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Kuhl, Jürgen, Alfred Honold, Lothar Schultheis, and Charles W. Tu. "Optical dephasing and orientational relaxation of wannier-excitons and free carriers in GaAs and GaAs/AlxGa1−xAs quantum wells." In Advances in Solid State Physics, 157–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/bfb0108011.

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Combescot, Monique, and Shiue-Yuan Shiau. "Wannier Excitons." In Excitons and Cooper Pairs, 34–107. Oxford University Press, 2015. http://dx.doi.org/10.1093/acprof:oso/9780198753735.003.0003.

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Combescot, Monique, and Shiue-Yuan Shiau. "Elementary Bosons, Wannier Excitons, and Frenkel Excitons." In Excitons and Cooper Pairs, 178–90. Oxford University Press, 2015. http://dx.doi.org/10.1093/acprof:oso/9780198753735.003.0005.

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La Rocca, G. C. "Wannier–Mott Excitons in Semiconductors." In Electronic Excitations in Organic Nanostructures, 97–128. Elsevier, 2003. http://dx.doi.org/10.1016/s1079-4050(03)31002-6.

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Vanderbilt, D., and R. Resta. "Chapter 5 Quantum Electrostatics of Insulators: Polarization, Wannier Functions, and Electric Fields." In Conceptual Foundations of Materials - A Standard Model for Ground- and Excited-State Properties, 139–63. Elsevier, 2006. http://dx.doi.org/10.1016/s1572-0934(06)02005-1.

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Agranovich, V. M., V. I. Yudson, and P. Reineker. "Hybridization of Frenkel and Wannier–Mott Excitons in Organic-Inorganic Heterostructures. Strong Coupling Regime." In Electronic Excitations in Organic Nanostructures, 317–53. Elsevier, 2003. http://dx.doi.org/10.1016/s1079-4050(03)31007-5.

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Conference papers on the topic "Exciton wannier"

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Khurgin, Jacob B. "Flexible Polaritons: Wannier Exciton-Plasmon Coupling in Metal-Semiconductor Structures." In CLEO: QELS_Fundamental Science. Washington, D.C.: OSA, 2019. http://dx.doi.org/10.1364/cleo_qels.2019.fm4d.6.

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Somaschi, N., S. Tsintzos, D. Coles, D. G. Lidzey, Z. Hatzopoulos, P. G. Lagoudakis, and P. G. Savvidis. "Strongly Coupled Hybrid Frenkel/Wannier-Mott Exciton Polaritons in a High Q Microcavity." In CLEO: QELS_Fundamental Science. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/cleo_qels.2013.jth2a.43.

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Varsha, Poonam Silotia, and Vinod Prasad. "Study of optical properties of Wannier-Mott exciton in spherical quantum dot in Kratzer potential." In 3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019). AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0002124.

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Yoshioka, Kosuke, Takuro Ideguchi, and Makoto Kuwata-Gonokami. "Quantum-Mechanical Inelastic Collisions of Wannier-Mott Excitons." In Quantum Electronics and Laser Science Conference. Washington, D.C.: OSA, 2010. http://dx.doi.org/10.1364/qels.2010.jthe110.

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Balkarey, Yuri I., Alexander S. Cohen, Mordukh I. Elinson, Michael G. Evtikhov, and Vladimir S. Posvyanskii. "Coherent state of Wannier-Mott excitons: transformations of nonlinear spatial structures." In Photonics West '97, edited by Marek Osinski and Weng W. Chow. SPIE, 1997. http://dx.doi.org/10.1117/12.275636.

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Kena-Cohen, Stephane, Russell J. Holmes, Vinod M. Menon, and Stephen R. Forrest. "Hybridization of Frenkel and Wannier-Mott excitons in an optical microcavity." In 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference. IEEE, 2006. http://dx.doi.org/10.1109/cleo.2006.4629044.

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Yeshchenko, O. A., M. M. Biliy, and Z. Z. Yanchuk. "Energy bands and Wannier-Mott excitons in Zn(P1-xAsx)2 and Zn1-xCdxP2 crystals." In SPIE Proceedings, edited by Galyna O. Puchkovska, Tatiana A. Gavrilko, and Olexandr I. Lizengevich. SPIE, 2004. http://dx.doi.org/10.1117/12.570025.

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Nizamoglu, Sedat, Xiaowei Sun, and Hilmi Volkan Demir. "Efficient migration of Mott-Wannier excitons to Frenkel excitons in hybrid organic/inorganic assembly of CdSe/ZnS nanocrystals in MDMO-PPV homopolymers." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343410.

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Nizamoglu, Sedat, Xiao Wei Sun, and Hilmi Volkan Demir. "Room-temperature, high-efficiency conversion of Mott-Wannier to Frenkel excitons in hybrid semiconductor quantum dot/polymer composites." In Quantum Electronics and Laser Science Conference. Washington, D.C.: OSA, 2011. http://dx.doi.org/10.1364/qels.2011.qtul6.

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