Search for dissertations about: "impurities"

Showing result 1 - 5 of 228 swedish dissertations containing the word impurities.

  1. 1. Effects of impurities on charge transport in graphene field-effect transistors

    Author : Marlene Bonmann; Chalmers University of Technology; []
    Keywords : carrier transport; electron and hole mobility; impurities; traps; graphene; field-effect transistors; microwave devices; saturation velocity; remote phonons;

    Abstract : In order to push the upper frequency limit of high speed electronics further, thereby extending the range of applications, new device technologies and materials are continuously investigated. The 2D material graphene, with its intrinsically extremely high room temperature charge carrier velocity, is regarded as a promising candidate to push the frequency limit even further. READ MORE

  2. 2. Multiscale modeling of atomic transport phenomena in ferritic steels

    Author : Luca Messina; Pär Olsson; Nils Sandberg; Pål Efsing; Pascal Bellon; KTH; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; diffusion; impurities; iron; metals; kinetic Monte Carlo; ab initio; mean field; defects; embrittlement; reactor pressure vessel; neural networks; Physics; Fysik;

    Abstract : Defect-driven transport of impurities plays a key role in the microstructure evolution of alloys, and has a great impact on the mechanical properties at the macroscopic scale. This phenomenon is greatly enhanced in irradiated materials because of the large amount of radiation-induced crystal defects (vacancies and interstitials). READ MORE

  3. 3. Gyrokinetic simulations of turbulent particle and heat transport in tokamaks

    Author : Daniel Tegnered; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; tokamak; plasma physics; turbulence; transport; gyrokinetics; TEM; ITG; impurities; fusion; Joint European Torus;

    Abstract : Fusion power is one of few viable sustainable means of energy production. The tokamak is arguable the most mature technology to magnetically confine fusion plasmas. In these devices, heat and particle transport is dominated by small-scale turbulent fluctuations. READ MORE

  4. 4. Gyrokinetic simulations of microturbulence and transport in tokamak plasmas

    Author : Daniel Tegnered; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ITG; Joint European Torus; impurities; transport; fusion; TEM; tokamak; turbulence; plasma physics; gyrokinetics;

    Abstract : Fusion power is one of few viable and sustainable means of energy production. The tokamak is arguable the most mature technology to magnetically confine fusion plasmas. In these devices, heat and particle transport is dominated by small-scale turbulent fluctuations. READ MORE

  5. 5. Out of the Dark and into the Light - Microscopic Analysis of Bright, Dark and Trapped Excitons

    Author : Maja Feierabend; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; density matrix formalism; localized states; impurities; dark excitons; strain; transition metal dichalcogenides; Bloch equations;

    Abstract : Atomically thin transition metal dichalcogenides (TMDs) have been in the focus of current research due to their efficient light-matter interaction, as well as the remarkably strong Coulomb interaction that leads to tightly bound excitons. Due to their unique band structure, TMDs show a variety of optically accessible bright and inaccessible dark excitons. READ MORE