Sökning: "ambipolar diffusion"
Visar resultat 1 - 5 av 8 avhandlingar innehållade orden ambipolar diffusion.
1. Threshold and Temperature Characteristics of InGa(N)As-GaAs Multiple Quantum Well Lasers
Sammanfattning : Semiconductor lasers emitting in the 1.3 μm regime are of interest for applications in access-networks like fiber-to-the-home and radio-over-fiber systems. Suchfiber optical networks are expected to replace the copper-based access-networks currently in use due to a continuously increasing demand on user bandwidth. LÄS MER
2. Dilute Nitride Lasers and Spectrally Engineered Semiconductor Laser Resonators
Sammanfattning : The first part of this thesis deals with long wavelength (1.2-1.3 um) InGaAs(N)multiple quantum-well (QW) lasers grown on GaAs, with the aim of understandingand improving their threshold and temperature characteristics. The epitaxialmaterial is grown by molecular beam epitaxy (MBE). LÄS MER
3. Studies of Charge Transport Processes in Dye-sensitized Solar Cells
Sammanfattning : Dye-sensitized solar cells (DSCs) have attained considerable attention during the last decade because of the potential of becoming a low cost alternative to silicon based solar cells. Although efficiencies exceeding 10% in full sunlight have been presented, major improvements of the system are however limited. LÄS MER
4. Impact of carrier localization on recombination in InGaN quantum wells with nonbasal crystallographic orientations
Sammanfattning : The modern InGaN technology demonstrates high efficiencies only in the blue spectral region and low current operation modes. The growth of InGaN quantum wells (QWs) on nonbasal crystallographic planes (NBP) has potential to deliver high-power blue and green light emitting diodes and lasers. LÄS MER
5. Optical studies of carrier transport and fundamental absorption in 4H-SiC and Si
Sammanfattning : The Fourier transient grating (FTG) technique and a novelspectroscopic technique, both based on free carrier absorption(FCA) probing, have been applied to study the carrierdiffusivity in 4H-SiC and the fundamental absorption edge in4H-SiC and Si, respectively. FTG is a unique technique capable of detecting diffusioncoefficient dependence over a broad injection interval rangingfrom minority carrier diffusion to the ambipolar case. LÄS MER