Sökning: "low-dimensional structures"
Visar resultat 1 - 5 av 61 avhandlingar innehållade orden low-dimensional structures.
1. Electron Transport in Low Dimensional Systems
Sammanfattning : This thesis consists of experimental studies of transport properties in high mobility two dimensional electron gases (2DEGs). Two material systems are used, an AlGaAs/GaAs heterojunction and a GaInAs/InP quantum well. LÄS MER
2. Optical Properties of Low Dimensional Semiconductor Materials
Sammanfattning : This dissertation presents a serial study on optical properties of different semiconductor materials. Three main types of studies are addressed: The role of doping levels of N and Al atoms in the room-temperature photoluminescence (PL) of 4H-SiC films for optoelectronic applications; the use of a basic Monte Carlo method combined with probability calculations of the time-dependent Schroedinger equation to manifest multi-photon absorption and emission of II-VI compound quantum dots (QDs) for bioimaging; a theoretical quantum chemistry approach to study of structure and optical properties of InGaAsN and GaAs clusters for laser technology applications. LÄS MER
3. Nanoelectronic Devices Based on Low-Dimensional Semiconductor Structures
Sammanfattning : The present thesis reports on results from the fabrication technology development and the corresponding electrical transport measurements of low-dimensional semiconductor structures. The focus of the work has been directed towards two parts: the ballistic transport in nanostructure devices at room temperature, and the development of a charge-sensing technique for quantum dots (QD) in nanowires. LÄS MER
4. Magnetic frustration and low-dimensional magnetism : in transition metal fluorophosphates and square-lattice intermetallic compounds
Sammanfattning : Solids can display a variety of vastly different magnetic properties. Besides the generally well known ferromagnets, antiferromagnets with their antiparallel arrangements of magnetic moments can exhibit a wide range of complex magnetic behavior such as magnetic frustration or low-dimensional antiferromagnetism. LÄS MER
5. Quantum electronic transport in low-dimensional semiconductors
Sammanfattning : Electronic transport is studied at low temperatures in two-dimensional electron gases (2DEGs) and in mesoscopic semiconductor microstructures. The method of microwave-detection of the Shubnikov-de Haas effect for the contact-free characterisation of transport properties of 2DEGs is explored using both magnetic-field modulation and light-induced carrier modulation. LÄS MER