Sökning: "exciton theory"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden exciton theory.

  1. 1. Microscopic Theory of Exciton Dynamics in Two-Dimensional Materials

    Författare :Samuel Brem; Chalmers University of Technology; []
    Nyckelord :exciton-phonon interaction; van der Waals materials; relaxation dynamics; excitons; 2D materials; density matrix formalism;

    Sammanfattning : Transition Metal Dichalcogenides (TMDs) present a giant leap forward towards the realization of nanometer-sized quantum devices. As a direct consequence of their truly two-dimensional character, TMDs exhibit a strong Coulomb-interaction, leading to the formation of stable electron-hole pairs, so-called excitons. LÄS MER

  2. 2. The choreography of protein vibrations : Improved methods of observing and simulating the infrared absorption of proteins

    Författare :Eeva-Liisa Karjalainen; Andreas Barth; Astrid Gräslund; Timothy A. Keiderling; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Infrared spectroscopy; FTIR; protein; atpase; amyloid; caged compound; amide I; transition dipole coupling; exciton theory; simulation; Molecular biophysics; Molekylär biofysik; Biophysics; biofysik;

    Sammanfattning : The work presented in this thesis has striven toward improving the capability to study proteins using infrared (IR) spectroscopy. This includes development of new and improved experimental and theoretical methods to selectively observe and simulate protein vibrations. LÄS MER

  3. 3. Microscopic Theory of Externally Tunable Exciton Signatures of Two-Dimensional Materials

    Författare :Maja Feierabend; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transition metal dichalcogenides; dark excitons; Bloch equations; magnetic field; density matrix formalism; organic inorganic heterostructures; localized states; strain;

    Sammanfattning : Atomically thin transition metal dichalcogenides (TMDs) are in the focus of current research due to their efficient light-matter interaction and the remarkably strong Coulomb interaction that leads to tightly bound excitons. Due to their unique band structure, TMDs show a variety of bright and optically inaccessible dark excitonic states. LÄS MER

  4. 4. Atomic Scale Modelling in Photoelectrocatalysis : Towards the Development of Efficient Materials for Solar Fuel Production

    Författare :Giane B. Damas; Carlos Moyses Araujo; Rajeev Ahuja; Clas Persson; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Photocatalytic hydrogen production; polymeric materials; donor-acceptor architecture; small molecules; density functional theory; hydrogen binding free energies; exciton binding energies; electrocatalysis; carbon dioxide conversion; formic acid production; Sn-based electrodes; Tin oxides; Ru-complexes; Metal Organic Frameworks; carbon dioxide capture.;

    Sammanfattning : Using sunlight to produce valuable chemicals has been pointed out as an interesting alternative to deal with the well-known environmental problem related to the use of fossil fuels for energy generation. Thus, it is crucial for this field the development of novel photocatalysts that could drive the uphill reactions with high efficiency while presenting low price and toxicity. LÄS MER

  5. 5. Electrical and Optical Properties of AlGaAs/GaAs Aperiodic Superlattices and Resonant Tunneling Diodes. Theory, Design and Applications

    Författare :Simon Mang Cao; Chalmers University of Technology; []
    Nyckelord :exciton-assisted transport; miniband; high-speed quantum electronics; optical properties; ultrafast optoelectronics; field-induced transport; irregular superlattices; nanometer-scale heterostructures; laser diodes; resonant tunneling;

    Sammanfattning : The objective of the work presented in this thesis is to study quantum transport and optical properties of aperiodic superlattices and resonant tunneling diodes using III-V semiconductor heterostructures grown by molecular beam epitaxy. The study follows a procedure of theoretical modeling, computer-aided design and simulation, sample growth, and measurements. LÄS MER