Sökning: "metastable levels"

Visar resultat 16 - 20 av 26 avhandlingar innehållade orden metastable levels.

  1. 16. Capacitance transient measurements on point defects in silicon and silicol carbide

    Författare :Hanne Kortegaard Nielsen; Anders Hallén; F. Damie Auret; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; Elektronik; Electronics; Elektronik;

    Sammanfattning : Electrically active point defects in semiconductor materials are important because they strongly affect material properties like effective doping concentration and charge carrier lifetimes. This thesis presents results on point defects introduced by ion implantation in silicon and silicon carbide. LÄS MER

  3. 17. Electron Paramagnetic Resonance studies of negative-U centers in AlGaN and SiC

    Författare :Xuan Thang Trinh; Nguyen Tien Son; Erik Janzén; Jan Stehr; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Silicon (Si) is the most commonly used n-type dopant in AlGaN, but the conductivity of Si-doped AlxGa1-xN was often reported to drop abruptly at high Al content (x>0.7) and the reason was often speculated to be due to either compensation by deep levels or self-compensation of the so-called DX (or negative-U) center. LÄS MER

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

    Författare :Vitalie Boţan; Lars Nordström; Sveatoslav Moskalenko; Pavlos Lagoudakis; Uppsala universitet; []
    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

  5. 19. Upconversion in Er doped silica : - characterization and modeling

    Författare :Dmitry Khoptyar; Bozena Jaskorszynska; Anders Bjarklev; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : Further increase of erbium concentrations in Er-doped amplifiers and lasers is needed for the design of efficient, reliable, compact and cost-effective components for telecommunications and other photonic applications. However, this is hindered by Er concentration dependent loss mechanism known as upconversion. LÄS MER

  7. 20. Synthesis, characterisation and applications of iron oxide nanoparticles

    Författare :German Salazar Alvarez; Manoun Muhammed; Jarl B. Rosenholm; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; biochemistry; electricity and magnetism; optics; Materialvetenskap; Materials science; Teknisk materialvetenskap;

    Sammanfattning : Further increase of erbium concentrations in Er-doped amplifiers and lasers is needed for the design of efficient, reliable, compact and cost-effective components for telecommunications and other photonic applications. However, this is hindered by Er concentration dependent loss mechanism known as upconversion. LÄS MER