Sökning: "carrier dynamics"

Visar resultat 1 - 5 av 82 avhandlingar innehållade orden carrier dynamics.

  1. 1. Spatiotemporal carrier dynamics in graphene

    Författare :Roland Jago; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spatiotemporal dynamics; density matrix formalism; graphene; relaxation dynamics; carrier multiplication; Bloch equations; photoconduction effect; bolometric effect;

    Sammanfattning : Graphene as an atomically thin material exhibits remarkable optical and electronic properties that suggest its technological application in novel optoelectronic devices, such as graphene-based photodetectors and lasers. To understand the properties of such devices on a microscopic level, we study the interplay of optical excitation, carrier-carrier, carrier-phonon, and carrierphoton scattering as well as diffusion processes. LÄS MER

  2. 2. Electron-Lattice Dynamics in pi-Conjugated Systems

    Författare :Magnus Hultell (Andersson); Sven Stafström; Alexander Onipko; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Polaron dynamics; Exciton dynamics; pi-conjugated systems; Su-Schrieffer-Heeger SSH model; Adiabaticity; Charge carrier transport; Organic electronics.; Computational physics; Beräkningsfysik;

    Sammanfattning : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. LÄS MER

  3. 3. Charge Carrier Dynamics in Novel Solar Materials : Ultrafast Spectroelectrochemistry

    Författare :Alireza Honarfar; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; charge carrier dynamics; quantum dots; solar cells; trion decay;

    Sammanfattning : The constant increase in global energy demand makes it inevitable to find clean means of energy production. Among renewable energy sources, the Sun is the most available source which makes it a versatile solution for energy needs. Tremendous efforts are made to invent and develop new materials for light to energy conversion. LÄS MER

  4. 4. Carrier dynamics in semiconductor quantum dots

    Författare :Jörg Siegert; Ari Friberg; Jesper Mørk; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; quantum dots; photoluminescence; time-resolved; spectroscopy; semiconductor; Optics; Optik;

    Sammanfattning : This thesis presents results of time-resolved photoluminescence experiments conducted on several different self-assembled InGaAs/GaAs and InAs/GaAs semiconductor quantum dot (QD) structures. Depending on the application in mind, different structural, electronic or optical properties have a different weight of importance. LÄS MER

  5. 5. Modal Dynamics of Vertical-Cavity Surface-Emitting Lasers

    Författare :Johan Gustavsson; Chalmers University of Technology; []
    Nyckelord :transverse modes; noise; modeling; Semiconductor laser; dynamics; vertical-cavity surface-emitting laser;

    Sammanfattning : In this work, a comprehensive dynamic model has been developed for simulating a novel semiconductor laser type, referred to as the Vertical-Cavity Surface-Emitting Laser (VCSEL). The high-speed behavior was simulated and compared to experiments, where excellent agreement was found. LÄS MER