Sökning: "Dielectric Functions"

Visar resultat 11 - 15 av 29 avhandlingar innehållade orden Dielectric Functions.

1. 11. A study of finite-size, non-perturbative and anisotropic effects on the Lifshitz-van der Waals forces and torque with material dielectric responses from first-principles calculations

   Författare :Priyadarshini Thiyam; Clas Persson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lifshitz-van der Waals forces; Casimir torque; optical calculations with density functional theory; phosphorus; phosphorene;

   Sammanfattning : The van der Waals and the Casimir-Lifshitz forces are forces of attraction that exist between neutral polarizable bodies due to quantum fluctuations. They can be repulsive depending on the material properties and the geometry of the system. LÄS MER

3. 12. Metal Gate Technology for Advanced CMOS Devices

   Författare :Gustaf Sjöblom; Jörgen Olsson; Stefan de Gendt; Uppsala universitet; []
   Nyckelord :Electronics; metal gate; high-k dielectrics; titanium nitride; zirconium nitride; MOSFET; thin film; work function; XPS; Elektronik;

   Sammanfattning : The development and implementation of a metal gate technology (alloy, compound, or silicide) into metal-oxide-semiconductor field effect transistors (MOSFETs) is necessary to extend the life of planar CMOS devices and enable further downscaling. This thesis examines possible metal gate materials for improving the performance of the gate stack and discusses process integration as well as improved electrical and physical measurement methodologies, tested on capacitor structures and transistors. LÄS MER

4. 13. Numerical Studies of Energy Gaps in Photonic Crystals

   Författare :Andreas Rung; Carl-Gustaf Ribbing; Norbert Kaiser; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; photonic crystals; polaritonic; periodic structures; Reststrahlen; band structure; energy gap; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The concept of photonic crystals was born in the late 1980's when two important letters were published that showed the possibility to control light propagation by a periodic structure. A photonic crystals consists of two or more materials with different dielectric functions periodically arranged on the length scale of light. LÄS MER

5. 14. 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

7. 15. Stealth radomes

   Författare :Sören Poulsen; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electromagnetic scattering; Dichroic structures; Frequency selective surface; Elektroteknik; FSS; Electrical engineering; Radomes;

   Sammanfattning : This dissertation deals with periodic structures that are used as free-space electromagnetic filters. Two types of periodic structures are treated, namely the so called frequency selective surface (FSS) and the artificial puck plate (APP) structure. LÄS MER