Sökning: "Defect"

Visar resultat 6 - 10 av 798 avhandlingar innehållade ordet Defect.

1. 6. Magneto-optical studies of dilute nitrides and II-VI diluted magnetic semiconductor quantum structures

   Författare :Daniel Dagnelund; Irina Buyanova; Weimin Chen; Marek Godlewski; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dilute nitrides; DMS; defect; ODMR; optically detected magnetic resonance; spin injection; PLE; photoluminescence excitation; post-growth hydrogenation; heterojunction; Semiconductor physics; Halvledarfysik;

   Sammanfattning : This thesis work aims at a better understanding of magneto-optical properties of dilute nitrides and II-VI diluted magnetic semiconductor quantum structures. The thesis is divided into two parts. The first part gives an introduction of the research fields, together with a brief summary of the scientific results included in the thesis. LÄS MER

3. 7. Defect Engineering in Kesterite Materials for Thin Film Solar Cells

   Författare :Katharina Rudisch; Jonathan J. Scragg; Alain Lafond; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CZTS; thin film solar cells; defect engineering; composition-spread films; order disorder transition; intrinsic defects; secondary phases; Teknisk fysik med inriktning mot elektronik; Engineering Science with specialization in Electronics;

   Sammanfattning : Cu2ZnSnS4 has great potential to be applied as an earth abundant and non-toxic absorber material in thin film solar cells, based on its suitable optical properties. However, several challenges have prevented the achievable efficiencies from exceeding 12.6 %, which is well below marketable efficiencies compared to competing solar cell technologies. LÄS MER

4. 8. Computational Material Design : Diluted Magnetic Semiconductors for Spintronics

   Författare :Lunmei Huang; Rajeev Ahuja; Walter Temmerman; Uppsala universitet; []
   Nyckelord :Physics; Density functional theory; Diluted magnetic semiconductor; Ferromagnetism; Defect; Phase transition; High pressure; Thermal elastic constant; Fysik;

   Sammanfattning : The present thesis deals with the application of ab-initio electronic structure calculations based on density functional theory for material design.The correlation between magnetic properties and electronic structures has been investigated in detail for diluted magnetic semiconductors (DMS), which have promising application for spintronics devices. LÄS MER

5. 9. Polypropylene : Morphology, defects and electrical breakdown

   Författare :Sari J. Laihonen; Ulf W. Gedde; Erling Ildsten; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical engineering; polypropylene; poly propylene-stat-ethylene ; crystal structure; morphology; crystallinity; crystallization kinetics; lamellae; spherulite; defect; Kemiteknik; Chemical engineering; Kemiteknik;

   Sammanfattning : Crystal structure, morphology and crystallization kinetics of melt-crystallized polypropylene and poly(propylene-stat-ethylene) fractions with 2.7 to 11.0 mol% of ethylene were studied by differential scanning calorimeter, wide- and small-angle X-ray scattering, polarized light microscopy, transmission electron microscopy and infrared spectroscopy. LÄS MER

7. 10. Point defects and ion conduction in solid oxides: a first-principles case study of La2Zr2O7

   Författare :Joakim Nyman; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; proton; self compensation; hydrogen economy; DFT; La2Zr2O7; acceptor doping; lanthanum zirconate; oxygen vacancy; SOFC; pyrochlore; point defect; trapping; computational methods; solid oxide; charge compensation; first principles; ion conduction; solid oxide fuel cell; ceramic electrolyte; defect cluster; fuel cell; hydrogen;

   Sammanfattning : In the endeavor to attain a clean environment and sustainable energy consumption, the notion of a future hydrogen economy stands out as one of the grandest visions. Striving for this vision, a critical task lies in optimizing the performance of the fuel-cell devices responsible for extracting electric power from the energy stored in hydrogen molecules. LÄS MER