Electron microscopic and optical investigations of the indium distribution in GaAs capped InxGa1−xAs islands

Results from a structural and optical analysis of buried In${}_x$ Ga${}_{\text{1−x}}$ As islands carried out after the process of GaAs overgrowth are presented. It is found that during the growth process, the indium concentration profile changes and the thickness of the wetting layer emanating from a Stranski–Krastanow growth mode grows significantly. Quantum dots are formed due to strong gradients in the indium concentration, which is demonstrated by photoluminescence and excitation spectroscopy of the buried In${}_x$ Ga${}_{\text{1−x}}$ As islands.