Morphology, orientation relationship, and stability analysis of Cu2O nanoclusters on SrTiO3 (100)

Abstract

Reflection high energy electron diffraction, atomic force microscopy, and theoretical studies based on classical nucleation theory have been used to interpret the morphology, orientation relationship, and stability of Cu2O nanoclusters on SrTiO3 (100) (STO). We propose that the competing interfacial and elastic energies facilitate an in-plane rotation of the Cu2O clusters by 45° with respect to the STO substrate and stabilize Cu2O clusters on STO(100) with an orientation relationship of (001)Cu2O//(001)SrTiO3 and ⟨100⟩Cu2O//⟨110⟩SrTiO3. Our preliminary theoretical analysis also suggests that this particular orientation results in smaller critical nucleus sizes and lower nucleation barriers and also indicates a chemical potential (growth rate) dependence of the orientation relationship.