Sökning: "quantum wells"

Visar resultat 1 - 5 av 68 avhandlingar innehållade orden quantum wells.

  1. 1. Spectroscopic studies of III-V semiconductors in two, one and zero dimensions

    Författare :Dan Hessman; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; InAs-InP; low-dimensional structures; quantum wells; quantum dots; quantum wires; k.p calculations; type-II; photoluminescence; V grooves; Stranski Krastanow; single dot spectroscopy; GaAs-InP; III-V semiconductors; Fysicumarkivet A:1996:Hessman; InAs-GaAs; GaInAs-InP; Halvledarfysik; InP-GaInP; Semiconductory physics;

    Sammanfattning : In this thesis, spectroscopic studies of quantum wells (QWs), quantum wires (QWRs) and quantum dots (QDs) in III-V semiconductors are presented. The electronic structure of these low-dimensional structures have been studied by absorption, photocurrent, electroreflectance, photoluminescence (PL), and photoluminescence excitation (PLE) spectroscopy. LÄS MER

  2. 2. Lineshape in Quantum Cascade Lasers - Temperature, Screening and Broadening

    Författare :Rikard Nelander; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Quantum Cascade Lasers; quantum wells; spectral lineshape; Non-Equilibrium Green s Functions; screening; temperature dependence;

    Sammanfattning : This dissertation deals with the optical properties of Quantum Cascade Lasers (QCLs). Studies are performed using transport calculations employing the theory of Non-Equilibrium Green's Functions, and screening is studied within the Random Phase Approximation. Focus is put on the temperature dependent effects in THz QCLs. LÄS MER

  3. 3. Surface-normal multiple quantum well electroabsorption modulators : for optical signal processing and asymmetric free-space communication

    Författare :Stéphane Junique; Lars Thylén; Uzi Efron; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spatial light modulators; quantum wells; optical resonator; Fabry–Pérot cavity; electroabsorption modulator; free–space optical communication; Photonics; Fotonik;

    Sammanfattning : Electroabsorption is the physical phenomenon by which the absorption of light in a medium can be controlled by applying an electric field. The Quantum–Confined Stark Effect, which makes the absorption band–edge in quantum wells very field–dependent, together with the strong absorption peak provided by excitons, are the physical foundations for the success of electroabsorption modulators based on quantum well structures in telecommunication networks. LÄS MER

  4. 4. MOVPE Growth and Characterization of Low-Dimensional III-V Semiconductor Structures

    Författare :Niclas Carlsson; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Semiconductory physics; low-dimensional structures; metalorganic vapour phase epitaxy; quantum wells; self-assembled dots; quantum dots; Fysicumarkivet A:1998:Carlsson; Halvledarfysik;

    Sammanfattning : Metalorganic vapour phase epitaxy is used for growth of low-dimensional III-V semiconductor structures. The roughness of heterointerfaces in GaAs/GaInP quantum well structures is studied by photoluminescence emission from extremely narrow quantum wells. LÄS MER

  5. 5. Theory of electronic structure and transport in heterostructure nanowires

    Författare :Florinda Viñas Boström; NanoLund; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; electronic structure; electron transport; nano; quantum; InAs; GaSb; topological; nanowires; quantum dots; Fysicumarkivet A:2020:Vinas Boström;

    Sammanfattning : Today, semi-conductor nanowires can be grown with very high precision, using epitaxy. This allows for studies of new nanowire-based quantum devices, likely to be part of novel quantum technologies in the future. This thesis concerns nanostructures based on InAs nanowires. LÄS MER