Formation of Cu2O quantum dots on SrTiO3 (100): Self-assembly and directed self-assembly

Abstract

Cu 2 O quantum dots (QDs) have been synthesized on single crystal SrTiO3 (100) substrates with focused ion beam (FIB) modification using oxygen plasma-assisted molecular beam epitaxy. In a set of experiments, QD growth location has been controlled using FIB implants to modify the growth surface in discrete locations prior to dot synthesis. Atomic force microscopy has been used to characterize this directed self-assembly of oxide QDs. QDs have been observed to form first in the FIB generated surface features, filling those features before additional QDs have nucleated on neighboring, unmodified surface regions. The nature of the QDs on the modified surface is compared to those grown on unmodified substrate regions. While FIB modification provides lateral control over QDs, the QDs formed on the undamaged surfaces were more uniform in shape and size than those that nucleated in the FIB produced pits.