Crystal tilting of diamond heteroepitaxially grown on vicinal Ir∕SrTiO3(001)

In the present study SrTiO3 crystals with vicinal (001) surfaces inclined 3° and 5° towards [110] and [100], respectively, have been used to deposit iridium layers and subsequently epitaxial diamond films. The iridium grows on top of the vicinal SrTiO3(001) with a perfect cube-on-cube registry. In contrast, the diamond films on the iridium show a strong additional tilting of up to 2°. A model is proposed which explains the effect by the preferential incorporation of misfit dislocations due to the stress anisotropy on the vicinal substrate planes taking into account the lattice misfit and the islandlike growth mode of diamond. The experimental observations and their explanation suggest that the epitaxial diamond alignment on iridium takes place during lateral growth within the first few nanometers.