Sökning: "Low dimensional"

Visar resultat 1 - 5 av 868 avhandlingar innehållade orden Low dimensional.

1. 1. Electron Transport in Low Dimensional Systems

   Författare :Peter Ramvall; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; high mobility; low-dimensional structures; III-V semiconductors; quantum wells; heterojunctions; quantum Hall effect; edge channels; Shubnikov-de Haas effect; alloy-disorder scattering; Y-branch switch; two dimensional electron gas; Fysik; Fysicumarkivet A:1996:Ramvall; Physics; spin splitting; mag;

   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

3. 2. Optical Properties of Low Dimensional Semiconductor Materials

   Författare :Tiantian Han; Ying Fu; Per-Olof Holtz; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Semiconductor; Low dimensional; optics; Physics; Fysik;

   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

4. 3. Magnetic frustration and low-dimensional magnetism : in transition metal fluorophosphates and square-lattice intermetallic compounds

   Författare :Stefanie Siebeneichler; Anja-Verena Mudring; Ulrich Häussermann; Sven Lidin; Kenneth R. Poeppelmeier; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetic frustration; low-dimensional magnetism; ionothermal synthesis; powder neutron diffraction; fluorophosphates; intermetallics; Physical Chemistry; fysikalisk kemi;

   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. 4. Surface analysis of low dimensional materials : revealing their electronic properties by advanced spectroscopy

   Författare :Vladimir Miranda la Hera; Thomas Wågberg; Eduardo Gracia-Espino; Tomas Edvinsson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Low-dimensional materials; surface science; surface-sensitive techniques; angle-resolved photoemission spectroscopy; ultraviolet photoemission spectroscopy; electronic properties;

   Sammanfattning : Low-dimensional materials (0D, 1D, 2D) have been widely used to develop modern miniaturized (micro- and nano-) technology. The use of these materials come from their extraordinary optical, electrical, thermal, and mechanical properties, which are very different from the bulk crystal. LÄS MER

7. 5. Quantum electronic transport in low-dimensional semiconductors

   Författare :Heiner Linke; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum transport; two-dimensional electron gas; contact-free characterisation; ballistic transport; mesoscopic; electron billiard; quantum dot; electron-electron interaction; non-linear; phase breaking; Halvledarfysik; Fysicumarkivet A:1997:Linke; non-symmetric conductio; Semiconductory physics; low-dimensional structures;

   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