Formation of self-assembled InAs quantum dots on (110) GaAs substrates

The formation of indium arsenide self-assembled quantum dots (QDs) has been observed on (110) GaAs substrates. The quantum dots were grown using solid source molecular-beam epitaxy. Both (110) and (100) GaAs wafers were placed in the growth chamber and grown on simultaneously. QDs were found to form on the (110) GaAs substrate when grown upon a thin AlAs layer. Buried layers of InAs were studied using photoluminescence spectroscopy, while surface layers were studied by atomic force microscopy. While the luminescence spectra for simultaneously grown (110) and (100) QDs are similar in structure, the changes in each sample’s spectrum as a function of both temperature and excitation intensity suggest quantum dot density is over an order of magnitude lower on (110) samples than it is on the (100) samples. This difference is conditionally confirmed by atomic force microscopy studies.