Sökning: "quantum wells"

Visar resultat 21 - 25 av 79 avhandlingar innehållade orden quantum wells.

1. 21. Quantum-Confined Stark Effect in Artificially Made Quantum Well Structures

   Författare :Weiquan Chen; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : The objective of the work presented in this thesis is to study the quantum-confined Stark effect in differently shaped quantum well structures. This effect has shown great interest and significant applications in optoelectronic devices. Most of the studies and applications have focused on square quantum wells. LÄS MER

3. 22. 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

4. 23. Carrier dynamics in blue and green InGaN LED structures

   Författare :Rinat Yapparov; Saulius Marcinkevičius; Ulrich Theodor Schwarz; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; InGaN quantum wells; interwell transport; near-field scanning optical microscopy; internal quantum efficiency; V-defects; InGaN-kvantbrunnar; transport mellan brunnar; optisk mikroskopi med närafältsskanning; intern kvanteffektivitet; V-defekter; Physics; Fysik; Optics and Photonics; Optik och fotonik;

   Sammanfattning : This thesis focuses on effects that are critical to achieving high internal quantum efficiency (IQE) in GaN-based light-emitting diodes (LEDs) that emit in a broad spectral range, from violet to green-yellow. These effects include interwell carrier transport in multiple quantum well (QW) structures, lateral transport in the QW plane, and radiative and nonradiative recombination. LÄS MER

5. 24. Epitaxy of GaAs-based long-wavelength vertical cavity lasers

   Författare :Carl Asplund; KTH; []
   Nyckelord :gainnas; ingaas; quantum wells; movpe; mocvd; vertical cavity laser; bcsel; long-wavelength; epitaxy; xrd; dbr;

   Sammanfattning : Vertical cavity lasers (VCLs) are of great interest aslow-cost, high-performance light sources for fiber-opticcommunication systems. They have a number of advantages overconventional edge-emitting lasers, including low powerconsumption, efficient fiber coupling and wafer scalemanufacturing/testing. LÄS MER

7. 25. The band offset and the critical layer thickness in III-V compound semiconductor heterostructures

   Författare :Shu Min Wang; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; interface morphology; molecular beam epitaxy; band offset; transmission electron microscopy; InGaAs; strain; photoluminescence; critical layer thickness; quantum wells; heterostructures; III-V compounds;

   Sammanfattning : .... LÄS MER