In focus of this report are the mechanisms of formation, propagation, and interaction of growth defects in heteroepitaxial diamond films along with their impact on the optical emission properties of N- and Si-vacancy (NV and SiV) color centers. Here, we analyze and discuss the properties of incoherent grain boundaries (IGBs) and extended defects in a nitrogen- and boron-doped heterodiamond nucleated and grown on Ir(001) via bias-enhanced nucleation and chemical vapor deposition techniques. We show that the low-angle IGBs alter the structural and optical emission properties of NV and SiV complexes by subduing NV emission and supporting the formation of interstitial Si-vacancy complexes dominating in the faulted IGB regions. We also demonstrate that the IGB-confined threading dislocations are responsible for the vertical transport and incorporation of Si impurities in thick layers, leading to an enhanced SiV emission from the IGBs.
