InAs quantum dots grown on the $\mathrm{GaAs}\mathrm{}\left(113\right)A$ and $\mathrm{GaAs}\left(1\mathrm{}¯1¯3¯\right)B$ surfaces: A comparative STM study

InAs quantum dots (QD’s) were grown on $\mathrm{GaAs}\mathrm{}\left(113\right)A$ and $\mathrm{GaAs}\left(1\mathrm{}¯1¯3¯\right)B$ substrates by molecular-beam epitaxy. Atomically resolved scanning tunneling microscopy images acquired in situ from uncapped samples reveal the shape of the QD’s including the atomic structure of their main bounding facets. On the $\mathrm{}\left(113\right)A$ substrate the QD’s are elongated along $\left[332¯\right]$ with a wide size distribution, whereas on $\left(1\mathrm{}¯1¯3¯\right)$$B$ they are rather round and exhibit a more uniform size distribution. These observations are related to the different morphology of the substrates before QD formation. The differences in shape, size, and size distribution are discussed in terms of facet growth kinetics.