Indium Segregation and Enrichment in Coherent ${\mathrm{In}}_{\mathit{x}}{\mathrm{Ga}}_{1-\mathit{x}}\mathrm{As}/\mathrm{GaAs}$ Quantum Dots

Significant differences in the image features of ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ quantum dots (QDs) grown on (001) and vicinal (001) GaAs were seen in [001] on-zone bright-field transmission electron microscope images. Simulated images were obtained by modeling the strain field distribution of the QDs with finite element analysis and then using this model in dynamical electron diffraction contrast simulations. Comparison of the experimental images and the simulated images shows that (i) In segregation exists in the QDs and (ii) the average In content of the QDs is higher than the average In content of the film.