Sökning: "electron-phonon scattering"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden electron-phonon scattering.

1. 1. Tight-binding calculations of electron scattering rates in semiconducting zigzag carbon nanotubes

   Författare :Kannan Thiagarajan; Ulf Lindefelt; Hans-Erik Nilsson; Sven Öberg; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Tight-binding; carbon nanotubes; electron-phonon scattering; backscattering; forward scattering; Semiconductor physics; Halvledarfysik;

   Sammanfattning : The technological interest in a material depends very much on its electrical, magnetic, optical and/or mechanical properties. In carbon nanotubes the atoms form a cylindrical structure with a diameter of the order 1 nm, but the nanotubes can be up to several hundred micrometers in length. LÄS MER

3. 2. Electron-Phonon Interactions in Transition Metal Oxides Studied by Resonance Raman Scattering

   Författare :Jakob Andreasson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Franck-Condon; Fr ohlich interaction; higher order scattering; perovskite; transition metal oxide; two-phonon; oxygen breathing mode; Raman spectroscopy;

   Sammanfattning : In this thesis, studies of strong electron-phonon interactions in a number of transition metal oxides are presented. Two different electron-phonon interaction mechanisms are identified; Franck-Condon scattering and infrared active longitudinal optical (IR LO) two-phonon activation. LÄS MER

4. 3. Monte Carlo simulation of electron transport in semiconducting zigzag carbon nanotubes

   Författare :Kannan Thiagarajan; Ulf Lindefelt; Hans-Erik Nilsson; Michele Goano; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon nanotubes; Monte Carlo method; drift velocity; mobility; electron-phonon scattering; and electron-defect scattering.;

   Sammanfattning : Since the advent of nanoscale material based electronic devices, there has been a considerable interest in exploring carbon nanotubes from fundamental science and technological perspectives. In carbon nanotubes, the atoms form a cylindrical structure with a diameter of the order 1nm. LÄS MER

5. 4. Quantum Materials Probed by Light and Electron Spectroscopy

   Författare :Karin von Arx; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; RIXS; superconductivity; electron- phonon coupling; quantum materials; spin-orbit coupling; ARPES;

   Sammanfattning : As new technologies rely heavily on materials’ properties, the quest for novel tunable electronic and magnetic materials occupies a large part of nowadays research efforts. Most promising materials are quantum materials, which exhibit a wide range of exotic electronic and magnetic phenomena and often show a great sensitivity to external perturbations such as temperature, pressure or chemical doping. LÄS MER

7. 5. Dynamic local structural symmetries and luminescence properties of the yellow emitting phosphor Ce3+-doped Y3Al5O12

   Författare :Yuan-Chih Lin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; free electron laser; neutron scattering; vibrational spectroscopy; phosphor; light emitting diode; luminescence; thermal quenching; garnet;

   Sammanfattning : This thesis centers on investigations of the local structure and vibrational properties of the oxide garnet Y3Al5O12 (YAG), which when substituted with a few percent of the activator ion Ce3+ to replace Y3+ (Y3−xCexAl5O12, YAG:Ce3+) is one of the most important phosphors for solid state lighting. The study builds on a comprehensive analysis of the nature of the phonons and localized vibrational modes in YAG:Ce3+ and how these depend on the Ce3+ concentration and temperature and how they affect key optical properties, such as the intensity and frequency of the emitted light. LÄS MER