Sökning: "Light emitting diode"

Visar resultat 6 - 10 av 49 avhandlingar innehållade orden Light emitting diode.

1. 6. Design and Fabrication of Light-Emitting Electrochemical Cells

   Författare :Andreas Sandström; Ludvig Edman; Ronald Österbacka; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Light-emitting electrochemical cell; fabrication; organic semiconductors; organic electronics; ambient fabrication; roll-to-roll; fysik; Physics;

   Sammanfattning : Glödlampan, en gång symbolen för mänsklig uppfinningsförmåga, är idag på väg att försvinna. Lysdioder och lågenergilampor har istället tagit över då dessa har betydligt längre livstid och högre effektivitet. LÄS MER

3. 7. Studies of Light Emitting Devices Based on Er-doped Si and SiGe Layered Structures

   Författare :Chun-Xia Du; Fransesco Priolo; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; electroluminescence; diode; transistor; hot electron; recombination; excitation; de-excitation; Auger effect; molecular beam epitaxy; Er; Si; SiGe;

   Sammanfattning : Doping with rare earth element erbium (Er) in Si has recently attracted a lot of research interest due to potential applications in Si-based opto-electronics. By using molecular beam epitaxy (MBE), precipitate-free Er-doping in Si has been made together with other co-dopants, e.g., oxygen (0) and fluorine (F), up to a level ∼1020 cm-3. LÄS MER

4. 8. Fabrication and Characterization of ZnO Nanorods Based Intrinsic White Light Emitting Diodes (LEDs)

   Författare :Nargis Bano; Omer Nour; Magnus Willander; David Rogers; Linköpings universitet; []
   Nyckelord :Zinc Oxide nanorods; White light emitting diode; Photoluminescence; Cathodoluminescence; Electroluminescence; Deep level transient spectroscopy DLTS ;

   Sammanfattning : ZnO material based hetero-junctions are a potential candidate for the design andrealization of intrinsic white light emitting devices (WLEDs) due to several advantages overthe nitride based material system. During the last few years the lack of a reliable andreproducible p-type doping in ZnO material with sufficiently high conductivity and carrierconcentration has initiated an alternative approach to grow n-ZnO nanorods (NRs) on other ptypeinorganic and organic substrates. LÄS MER

5. 9. Light emitting devices based on silicon nanostructures

   Författare :Nenad Lalic; KTH; []
   Nyckelord :;

   Sammanfattning : Although silicon is the dominant semiconductor today, lightemitting devices are currently based on compound semiconductorsdue to their direct band-gap, which promotes fast radiativerecombination. However, in nanometer-size silicon structures,carrier confinement enhances the radiative recombination,while, at the same time, suppresses diffusion to non-radiativerecombination centra, resulting in a significant increase inlight emission efficiency. LÄS MER

7. 10. 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