Lateral short range ordering of step bunches in InGaAs/GaAs superlattices

In the present paper we report on structural investigations of fivefold ${\mathrm{In}}_{\text{0.2}}{\mathrm{Ga}}_{\text{0.8}}\mathrm{As/GaAs}$ superlattices which have been grown by means of metal organic chemical vapor deposition on vicinal GaAs(001) substrates. Cross-sectional transmission electron micrographs exhibit an initially flat and nonfaceted grooved surface, while step bunching occurs during subsequent growth stages with an inclined vertical inheritance approximately 45° off the (001) direction. A reconstructed sample cross section on the base of high resolution x-ray diffraction data qualitatively confirms the local morphology proved by transmission electron microscopy. Moreover, a line shape analysis of diffusely scattered intensity using Gauss profiles indicates a lateral short range ordering of step bunches.