Formation process of and lattice parameter variation in InAs/GaAs quantum dots dependent on the growth parameters

Reflection high-energy electron diffraction, atomic force microscopy, and transmission electron microscopy measurements were used to investigate the dependences of the formation process and the strain variation on the As4/In ratio and the substrate temperature in InAs/GaAs quantum dots (QDs) grown by using molecular beam epitaxy. The variations of the lattice constants of the InAs wetting layer and the InAs QDs were significantly affected by the As4/In ratio and the growth temperature. The magnitude in strain of the InAs QDs formed at a low substrate temperature was larger than that in InAs QDs grown at high substrate temperature. The present results can help to improve the understanding of the formation process of defect-free InAs QDs.