Sökning: "quantum dot"

Visar resultat 1 - 5 av 112 avhandlingar innehållade orden quantum dot.

  1. 1. Quantum-Dot Heat Engines

    Författare :Martin Josefsson; NanoLund; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; quantum dot; heat engine; thermoelectric; quantum thermodynamics; quantum transport; Fysicumarkivet A:2020:Josefsson;

    Sammanfattning : This thesis explores the possibilities of using quantum dots (QDs) in nanoscale energy har- vesters converting heat into electrical energy, i.e. heat engines. From a theory perspective, these possibilities have been investigated for almost two decades, and interest in them seem to continuously increase over time. LÄS MER

  2. 2. On the role of the electron-electron interaction in two-dimensional quantum dots and rings

    Författare :Erik Waltersson; Eva Lindroth; Stephanie Reimann; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; quantum ring; quantum dot molecule; electronic structure; two-dimensional; many-body physics; many-body perturbation theory; coupled cluster; coupled cluster singles and doubles; quantum logical gates; quantum computing; quantum control; quantum control algorithm; Electronic structure; Elektronstruktur; Physics; fysik;

    Sammanfattning : Many-Body Perturbation Theory is put to test as a method for reliable calculations of the electron-electron interaction in two-dimensional quantum dots. We show that second order correlation gives qualitative agreement with experiments on a level which was not found within the Hartree-Fock description. LÄS MER

  3. 3. Modelling of Quantum Transport in Nanostructures

    Författare :Dan Csontos; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; ballistic transport; quantum wire; quantum dot; resonant tunnelling; three-terminal; disorder; Physics; Fysik; Fysicumarkivet A:2002:Csontos; scattering matrix; quantum transport;

    Sammanfattning : In this thesis, theoretical studies of the transport properties of three nanoscale systems: one-dimensional (1D) quantum wires (QWRs), zero-dimensional (0D), laterally confined, double-barrier resonant tunnelling structures (DBRTSs) and three-terminal ballistic junctions (TBJs), have been performed. In the first part of the thesis, an overview of the realization and properties of such systems is given along with a description of modelling tools used in the calculations. LÄS MER

  4. 4. Linear and Nonlinear Transport in Quantum Nanostructures

    Författare :Anneli Löfgren; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetoconductance; mesoscopic; electron billiard; quantum dot; quantum ratchets; non-linear; symmetries; non-symmetric conduction; rectification; artificial material; Halvledarfysik; Fysicumarkivet A:2002:Löfgren; ballistic transport; quantum transport; 2DEG; Semiconductory physics; InP InGaAs; GaAs AlGaAs;

    Sammanfattning : In this thesis, electron transport in mesoscopic semiconductor nanostructures, in particular so-called electron billiards or quantum dots, is studied. The thesis can be divided into two areas: the linear response regime of transport, and the nonlinear response regime of transport. LÄS MER

  5. 5. Type-II interband quantum dot photodetectors

    Författare :Oscar Gustafsson; Mattias Hammar; Wenquan Ma; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; photodetector; quantum dot; infrared; MOVPE; thermal imaging; type-II; photoluminescence; III V; InSb; InGaSb; InAs; SRA - ICT; SRA - Informations- och kommunikationsteknik;

    Sammanfattning : Photon detectors based on single-crystalline materials are of great interest for high performance imaging applications due to their low noise and fast response. The major detector materials for sensing in the long-wavelength infrared (LWIR) band (8-14 µm) are currently HgCdTe (MCT) and AlGaAs/GaAs quantum wells (QW) used in intraband-based quantum-well infrared photodetectors (QWIPs). LÄS MER