Fig. 4. Facet plots obtained from the QD surface of a GaSb QD (a) without and (b) with In0.07Ga0.93As AS1404 layer. (c) and (d) are illustrations of GaSb QD on (0 0 1) GaAs surface and on (0 0 1) InGaAs surface. Relatively small QDs, which are elongated along the [1 1 0] direction, are observed for GaSb growth on GaAs, while large facet-related GaSb QDs are formed when InGaAs insertion layer is introduced before the QD growth.Figure optionsDownload full-size imageDownload as PowerPoint slide
We present an investigation of structural morphology of self-assembled GaSb QDs on (0 0 1) GaAs substrates. We have shown that when the InGaAs insertion layer is introduced, the obtained QD morphology considerably changes. The QD density decrement as well as QD size (height and diameter) enlargement are observed. Besides, the degree of QD elongation changes from a distinct elongation along the [1 1 0] direction to an isotropic shape when the indium content in InGaAs insertion layer increases. Finally, we have shown that the GaSb QDs on InGaAs have a clear (0 0 1) plateau on top and facet-related surfaces on the sidewalls.