Ordered InAs QDs using prepatterned substrates by monolithically integrated porous alumina

Abstract

In this work, we explore a method for obtaining site-controlled InAs quantum dots (QDs) on large areas of GaAs (0 0 1) pre-patterned surface. The patterning of the substrate is obtained by using a monolithically integrated nano-channel alumina (NCA) mask and transferring its self-ordering to the underlying GaAs substrate by continuing the anodization process once the GaAs surface is reached. After patterning, the GaAs substrate follows a low temperature process for surface preparation before epitaxial growth for QD formation. As a final result, we observe that the nanoholes act as preferential nucleation sites for InAs QD formation, with a filling factor close to unity, while the QD formation on the surface region between the pattern holes is completely suppressed.