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. To ensure the theory is in coherence with the reality, a qualitative study with five thermocouples in a test gr...
In this work, we report the selective area epitaxial growth of high quality InP in shallow trench isolation (STI) structures on Si (0 0 1) substrates 6° miscut toward (1 1 1) using a thin Ge buffer layer. We studied the impact of growth rates and steric hindrance effects on the nano-twin formation at the STI side walls. It was found that a too high...
GaN nanowire (NW) arrays have been fabricated by the electrodeless photoelectrochemical (PEC) etching method for the first time. Under appropriate conditions, the etching process is just a dislocation-hunted process, in which the etching solution "digs down'' along the threading dislocations, resulting in the formation of GaN NWs by preferentially ...
We report the selective area growth of InP layers in submicron trenches on Si (001) substrates by using a thin Ge buffer layer. The antiphase domain boundaries in InP layers are suppressed by engineering the local Ge surface profile. The mechanism of atomic step formation and the corresponding method for step density control are presented. We discu...
We investigate the band structure of a compressively strained In(Ga)As/In(0.53)Ga(0.47)As quantum well (QW) on an InP substrate using the eight-band k.p theory. Aiming at the emission wavelength around 2.33 mu m, we discuss the influences of temperature, strain and well width on the band structure and on the emission wavelength of the QW. The wavel...
The GaAs based InGaAs metamorphic structures and their growth by molecular beam epitaxy(MBE) are investigated. The controlling of the source temperature is improved to realize the linearly graded InGaAs metamorphic structure precisely. The threading dislocations are reduced. We also optimize the growth and annealing parameters of the InGaAs quantum...
Crack-free GaN epitaxial layer was obtained through inserting 80 nm graded AlGaN buffer layer between GaN epilayer and high temperature AlN buffer on 2-in Si(111) substrates by metal organic chemical vapor deposition. This paper investigated the influence of AlGaN buffer thickness on the structural properties of the GaN epilayer. It was confirmed f...
Up to 500 nm thick crack-free Al(0.25)Ga(0.75)N and Al(0.32)Ga(0.68)N epilayers have been grown on Si (111) substrates. The surface morphology of samples was investigated by an optical microscope and a scanning electron microscope (SEM). Pits and shale-like surface structure have been observed. XRD rocking curve measurements indicate the crystal qu...
