Selective formation and alignment of InAs quantum dots over mesa stripes along the [011] and [001] directions on GaAs (100) substrates

We have studied the selective formation of InAs self-organized quantum dots on top of [001]- and [011]-oriented mesa stripes on patterned GaAs (100) substrates. The GaAs stripes are also grown by selective area epitaxy. The dot density and spatial distribution depend on both the stripe orientation and the width of the (100) top facet of the stripe. The density is higher for stripes aligned in the [001] direction, and lower for those aligned in the [011] direction, respectively, when compared to that obtained on a planar substrate under the same growth conditions. In addition, the dot uniformity is improved by reducing the top facet width below 200 nm in the growth of the mesa stripes, and well-aligned rows of dots are obtained for sub-100-nm widths.