Transmission electron microscopy study ofInxGa1−xAsquantum dots on a GaAs(001) substrate

A transmission electron microscopy (TEM) investigation of the morphology of ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum dots grown on a GaAs(001) substrate has been carried out. The size and the shape of the quantum dots have been determined using bright-field images of cross-section TEM specimens and [001] on-zone bright-field images with imaging simulation from plan-view TEM specimens. The results suggest that the coherent quantum dots are lens shaped with base diameters of $25–40\hspace{0.5em}\mathrm{nm}$ and aspect ratios of height to diameter of $1:6–1:4$.