Sökning: "threading dislocation"
Visar resultat 1 - 5 av 15 avhandlingar innehållade orden threading dislocation.
1. Optimization of Metamorphic Materials on GaAs Grown by MBE
Sammanfattning : Advanced epitaxial technologies such as molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE) have enabled the idea of semiconductor heterostructures, which built up the foundation of the fast developing information and communication technology nowadays. Lattice mismatch has been a problem limiting designs of semiconductor heterostructures. LÄS MER
2. Novel Materials and Technologies for IR Optoelectronic Applications
Sammanfattning : This thesis focuses on novel III-V materials (InAs/GaSb type-II superlattices, T2SL, and dilute bismides) and metamorphic growth techniques for infrared optoelectronics all of which may find wide spread applications in telecommunication, energy harvesting and saving, sensing and imaging. Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) photodetectors at the atmospheric windows of 3-5 and 8-12 µm, respectively, are currently dominated by HgCdTe and quantum well infrared photodetectors. LÄS MER
3. Optical and Structural Characterization of GaN Based Hybrid Structures and Nanorods
Sammanfattning : GaN belongs to the group III nitrides and is today the material of choice for efficient blue light emission, enabling solid state white lighting by combining red, blue and green light emitting diodes (LED) or by having a blue LED illuminating a phosphor. By combining GaN quantum well (QW) structures with colloids, nanoparticles or polyfluorene films, LEDs may be fabricate at lower cost. LÄS MER
4. Magnetron Sputter Epitaxy of GaN
Sammanfattning : Electronic-grade GaN (0001) epilayers have been grown directly on Al2O3 (0001) substrates by reactive DC-magnetron sputter epitaxy (MSE) from a liquid Ga sputtering target in an Ar/N2 atmosphere. The as-grown GaN epitaxial film exhibit low threading dislocation density on the order of ≤ 1010 cm-2 obtained by transmission electron microscopy and modified Williamson-Hall plot. LÄS MER
5. Growth, characterization and processing of III-nitride semiconductors
Sammanfattning : The III-nitride semiconductor materials have wide direct bandgap ranging from 6.2 eV (AlN); through 3.4 eV (GaN) to 0.65 eV (InN). LÄS MER