Spatially Selective Formation of InAs Self-organized Quantum Dots on Patterned GaAs (100) Substrates

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Abstract
Self-organized InAs quantum dots are selectively formed on patterned GaAs (100) substrate by chemical beam epitaxy. Dot formation on top of sub-µm sized mesa stripes is a function of the stripe top width, the stripe orientation, as well as the growth conditions. The dot density is higher for stripes aligned in [001] direction, and lower for stripes aligned in the [011] direction, respectively, when compared to that obtained on a non-patterned substrate under the same growth conditions. We attribute these effects to dissimilar surface migration behavior of In adatoms on different side facets of the mesa stripes. The spatial distribution of the self-organized quantum dots (SOQDs) on top of [001] stripes becomes more uniform as the top facet width decreases, and self-alignment of the dots into well-defined rows is achieved by manipulating the growth conditions and mesa size.