Search for dissertations about: "exciton binding energies"

Showing result 1 - 5 of 7 swedish dissertations containing the words exciton binding energies.

2. 1. Atomic Scale Modelling in Photoelectrocatalysis : Towards the Development of Efficient Materials for Solar Fuel Production

   Author : Giane B. Damas; Carlos Moyses Araujo; Rajeev Ahuja; Clas Persson; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Photocatalytic hydrogen production; polymeric materials; donor-acceptor architecture; small molecules; density functional theory; hydrogen binding free energies; exciton binding energies; electrocatalysis; carbon dioxide conversion; formic acid production; Sn-based electrodes; Tin oxides; Ru-complexes; Metal Organic Frameworks; carbon dioxide capture.;

   Abstract : Using sunlight to produce valuable chemicals has been pointed out as an interesting alternative to deal with the well-known environmental problem related to the use of fossil fuels for energy generation. Thus, it is crucial for this field the development of novel photocatalysts that could drive the uphill reactions with high efficiency while presenting low price and toxicity. READ MORE

4. 2. Polarization-resolved photoluminescence spectroscopy of III-nitride quantum dots

   Author : Supaluck Amloy; Fredrik Karlsson; Per-Olof Holtz; Jørn M. Hvam; Linköpings universitet; []
   Keywords : ;

   Abstract : In this thesis, results from studies on (In)GaN quantum dots (QDs) are presented, including investigations of the structural, optical and electronic properties. The experimental studies were performed on GaN and InGaN QDs grown by molecular beam epitaxy, taking advantage of the Stranki-Krastanov growth mode for the GaN QD samples and the composition segregation for the InGaN QD samples. READ MORE

5. 3. Excitonic Effects and Energy Upconversion in Bulk and Nanostructured ZnO

   Author : Shula Chen; Irina Buyanova; Weimin Chen; Detlev M. Hofmann; Linköpings universitet; []
   Keywords : ;

   Abstract : Zinc Oxide (ZnO), a II-VI wurtzite semiconductor, has been drawing enormous research interest for decades as an electronic material for numerous applications. It has a wide and direct band gap of 3.37eV and a large exciton binding energy of 60 meV that leads to intense free exciton (FX) emission at room temperature. READ MORE

6. 4. Spectroscopic studies of InGaAs/GaAs/A1GaAs quantum dots and wires

   Author : Fredrik Karlsson; Manfred Bayer; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : It is demonstrated that the photoluminescence (PL) spectra of single selfassembled lnAs/GaAs quantum dots (QDs) are very sensitive to excitation energy and crystal temperature, which is explained in terms of modulation of the effective diffusivity of the photogenerated carriers affecting the capture probability into theQD. This effect results in a population of the QD with excess electrons, and can be used as a simple tool to create and study charged exciton complexes. READ MORE

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

   Author : Maja Feierabend; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; 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