Stacked structures In0.5Ga0.5As/GaAs quantum dots: Growth and characterization

Stacked structures of self-assembled In
_0.5
Ga
_0.5
As/GaAs quantum dots (QDs) have been grown using Metal-Organic Chemical Vapor Deposition (MOCVD) with different number of stacks. High Resolution X-Ray Diffraction (HR-XRD) and Transmission Electron Microscope (TEM) characterization revealed that the formation of stacked self-assembled In
_0.5
Ga
_0.5
As QDs on GaAs (100) substrates were misaligned vertically and no visible defect has been detected from the cross-sectional TEM characterization. In addition, photoluminescence (PL) peak position is blue-shifted and PL intensity dramatically increased with increasing number of stacks. The peak and intensity of the PL measurement strongly depend on the structural of stacked self-assembled QDs and also the number of QDs layers.