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The observation and interpretation of Frank stacking faults, Shockley stacking faults, Lomer dislocations, and 60° misfit dislocations, which have similar line shapes in the (001) In0.53Ga0.47As crystalline surface, are performed with the electron channeling contrast imaging (ECCI) technique. To minimize the backscattered electron (BSE) contrast that resulted from the surface morphology, a relatively flat region is first selected and compared with an atomic force microscopy (AFM) image and then, subsequently, examining ECCI with transmission electron microscopy (TEM)‐like invisibility criteria. By orthogonally choosing the diffraction vector g between (220) and (2‐20), misfit dislocations seem to be always visible but partially faint in the g parallel to the line direction on the surface. With respect to the image contrast, Frank stacking faults and Lomer dislocations are likely to be completely invisible for parallel g. The criteria are further confirmed by cross‐sectional TEM analysis, which shows a preferred homogeneous surface nucleation. [ABSTRACT FROM AUTHOR]

• Encapsulation of S-K grown InAs QDs on InP(0 0 1) substrate by InAlGaAs material. • No defect observed inside InAs QDs, at the interfaces, and in the capping layer. • A change in strain distribution observed in InAs QDs after InAlGaAs capping. • InAs QDs' photoluminescence intensity varies in function of capping layer thickness. • A two-step Non-uniform model explains the InAlGaAs capping process of InAs QDs. Stranski-Krastanow (S-K) grown self-assembled quantum dots (QDs) are considered as an efficient active layer for many optoelectronic applications, such as semiconductor laser, photodetector, due to the possibility to confine carriers in three dimensions. Towards the device application, the subsequent growth of an encapsulation layer is a key step to obtain the desired QDs-based heterostructures. In this work, we have studied step-by-step the encapsulation process of S-K grown InAs QDs/InP(0 0 1) by InAlGaAs (lattice matched to InP) in MOVPE. A detailed investigation with Electron Channeling Contrast Imaging (ECCI) and cross-sectional Transmission Electron Microscopy (TEM), indicated that after the InAlGaAs capping the partially relaxed, dome shaped InAs QDs are transformed into fully biaxially strained, truncated pyramids however without introducing any defects in the heterostructure. The study also presents the important role of the capping layer thickness on the QDs photoluminescence efficiency. The gradual change of the surface morphology during the encapsulation process, has been investigated step-by-step in-depth by atomic force microscopy. The morphological changes can be explained by a capping model based on the localized growth rates. We show that two growth steps of Non-uniform capping, where growth rates are different from each other, result in the successful planarization of the InAlGaAs capping without forming any defect. [ABSTRACT FROM AUTHOR]