Sökning: "Gallium Nitride GaN"

Visar resultat 6 - 10 av 16 uppsatser innehållade orden Gallium Nitride GaN.

1. 6. Investigating Optical-Field-Induced Currents in GaN using Ultrafast Lasers

   Magister-uppsats, Lunds universitet/Synkrotronljusfysik; Lunds universitet/Fysiska institutionen

   Författare :Vidar Flodgren; [2019]
   Nyckelord :GaN; gallium nitride; nanoscience; material science; ultrafast lasers; Yb Laser; Pharos Laser; titanium sapphire laser; device fabrication; lift-off; gold etching; optical-field-induced currents; modelling; matlab; Physics and Astronomy;

   Sammanfattning : This study saw the development of an experimental setup capable of generating and measuring optical-field-induced currents in a variety of nanodevices fabricated specifically for this project. Each device design features two metallic contacts, closely separated by about 5 micrometers, deposited onto a semiconductor or insulator substrate. LÄS MER

3. 7. Optimization of gas flow uniformity in enhancement of Metal Organic Chemical Vapor Deposition growth for III-nitrides

   Master-uppsats, Linköpings universitet/Halvledarmaterial

   Författare :Kevin Olsson; [2019]
   Nyckelord :material science; mocvd; gan; semiconductors; gallium; nitride; fluid dynamics; termoelements; thermocouple; injector; heat transfer; thermal distribution; graphite; HEMT; III-nitrides; hot-wall MOCVD system; GaN-on-SiC; gas flow profile; laminar flow;

   Sammanfattning : The thesis focuses on the gas flow profile optimization of a non-conventional injector in a hot-wall MOCVD system. The injector’s gas flow profile is simulated with CFD and demonstrates awell-behaved laminar flow with a parabolic profile. LÄS MER

4. 8. Using gallium nitride nanowires as STM probes

   Kandidat-uppsats, Lunds universitet/Synkrotronljusfysik; Lunds universitet/Fysiska institutionen

   Författare :Karolis Sulinskas; [2018]
   Nyckelord :STM; STS; Nanowire; GaN; InAs; Semiconductors; Physics and Astronomy;

   Sammanfattning : Gallium nitride (GaN) nanowires grown using catalyst-free metal organic vapor phase epitaxy were used as scanning tunneling microscope (STM) probes. The probes were prepared by placing a GaN nanowire on a tungsten STM probe using a nanomanipulator in a scanning electron microscope (SEM) and welding them together using an electron beam induced platinum deposition. LÄS MER

5. 9. Evaluation of graphene as a transparent electrode in GaN-based LEDs by PECVD synthesis of graphene directly on GaN

   Master-uppsats, Umeå universitet/Institutionen för fysik

   Författare :Linus Johansson; [2016]
   Nyckelord :PECVD; graphene; transparent electrode; gallium nitride; LED;

   Sammanfattning : A transparent conductive electrode (TCE) is an important component in many of our modern optoelectronic devices like photovoltaics, light emitting diodes and touch screens. These devices require good current injection and spreading as well as a high transparency. LÄS MER

7. 10. Quantum Chemical Feasibility Study of Methylamines as Nitrogen Precursors in Chemical Vapor Deposition

   Kandidat-uppsats, Linköpings universitet/Kemi

   Författare :Karl Rönnby; [2015]
   Nyckelord :Quantum Chemistry; Computational Chemistry; Density Functional Theory DFT ; B3LYP; Gaussian 4 G4 ; Chemical Vapor Deposition CVD ; Gallium Nitride GaN ; Aluminum Nitride AlN ; Ammonia NH3 ; Methylamine NH2CH3 ; Dimethylamine NH CH3 2 ; Trimethylamine NH CH3 3 ; Trimethylaluminum TMA ; Trimethylgallium TMG ; Decomposition; Adsorption;

   Sammanfattning : The possibility of using methylamines instead of ammonia as a nitrogen precursor for the CVD of nitrides is studied using quantum chemical computations of reaction energies: reaction electronic energy (Δ𝑟𝐸𝑒𝑙𝑒𝑐) reaction enthalpy (Δ𝑟𝐻) and reaction free energy (Δ𝑟𝐺). The reaction energies were calculated for three types of reactions: Uni- and bimolecular decomposition to more reactive nitrogen species, adduct forming with trimethylgallium (TMG) and trimethylaluminum (TMA) followed by a release of methane or ethane and surface adsorption to gallium nitride for both the unreacted ammonia or methylamines or the decomposition products. LÄS MER