Sökning: "Excitons"

Visar resultat 1 - 5 av 42 avhandlingar innehållade ordet Excitons.

  1. 1. Microscopic Mechanisms of the Formation, Relaxation and Recombination of Excitons in Two-Dimensional Semiconductors

    Detta är en avhandling från Gothenburg : Chalmers tekniska högskola

    Författare :Samuel Brem; [2019]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; relaxation dynamics; 2D materials; density matrix formalism; excitons; exciton-phonon interaction; Bloch equations;

    Sammanfattning : Monolayers of Transition Metal Dichalcogenides (TMDs) present a giant leap forward towards the realization of semiconductor devices with atomic scale thickness. As a natural consequence of their two-dimensional character TMDs exhibit a reduced dielectric screening, leading to the formation of unusually stable excitons, i.e. LÄS MER

  2. 2. Bose-Einstein Condensation of Magnetic Excitons in Semiconductor Quantum Wells

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Vitalie Boţan; Uppsala universitet.; [2006]
    Nyckelord :Physics; Bose-Einstein condensation; magnetic excitons; electron-hole pairs; electron-hole liquid; magnetorotons; magnetoplasmons; superfluidity; Fysik;

    Sammanfattning : In this thesis regimes of quantum degeneracy of electrons and holes in semiconductor quantum wells in a strong magnetic field are studied theoretically. The coherent pairing of electrons and holes results in the formation of Bose-Einstein condensate of magnetic excitons in a single-particle state with wave vector K. LÄS MER

  3. 3. Exciton-plasmon interactions in metal-semiconductor nanostructures

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Staffan Hellström; KTH.; [2012]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; plasmons; excitons; quantum dots; nanoparticles; FDTD; surface plasmon polaritons; QDIP; quantum dot infrared photodetector; polaritons;

    Sammanfattning : Semiconductor quantum dots and metal nanoparticles feature very strong light-matter interactions, which has led to their use in many photonic applications such as photodetectors, biosensors, components for telecommunications etc.Under illumination both structures exhibit collective electron-photon resonances, described in the frameworks of quasiparticles as exciton-polaritons for semiconductors and surface plasmon-polaritons for metals. LÄS MER

  4. 4. Electronic and Vibrational Coherence in Photosynthetic and Model Systems

    Detta är en avhandling från Chemical Physics, Lund University

    Författare :Mirianas Chachisvilis; [1996]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Kemi; Chemistry; Ultrafast relaxation; Porphyrins; Delocalization; Anisotropy; Wavepacket; Vibrational Coherence; Excitons; Electronic coherence; Energy transfer; Femtosecond spectroscopy; Photosynthesis;

    Sammanfattning : Ultrafast optical response and excitation energy dynamics in light harvesting pigment-protein complexes and in a few model systems have been studied both experimentally and theoretically. Femtosecond light pulses were employed to excite the system and monitor the subsequent time evolution of the transient absorption kinetics and anisotropy. LÄS MER

  5. 5. Complex Excitations in Advanced Functional Materials

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Johann Lüder; Uppsala universitet.; [2016]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray Absorption Spectroscopy; Photoelectron Spectroscopy; Adsorption; Phthalocyanines; Biphenylene; Excitons; Functional Materials;

    Sammanfattning : Understanding the fundamental electronic properties of materials is a key step to develop innovations in many fields of technology. For example, this has allowed to design molecular based devices like organic field effect transistors, organic solar cells and molecular switches. LÄS MER