Nitrogen-vacancy centers in epitaxial laterally overgrown diamond: towards up-scaling of color center-based quantum technologies

Abstract Providing high-quality, single-crystal diamond (SCD) with a large area is desirable for up-scaling quantum technology applications that rely on color centers in diamond. Growth methods aiming to increase the area of SCD are an active research area. Native color centers offer a sensitive probe for local crystal quality in such novel materials e.g. via their reaction to stress. In this work, we investigate individual native nitrogen-vacancy (NV) centers in SCD layers manufactured via laterally overgrowing hole arrays in a heteroepitaxially grown large-scale substrate. Heteroepitaxy has become a common tool for growing large SCDs; however, achieving the high crystal quality needed for quantum applications remains a challenge. In the overgrown layer, we identify NV centers with spin-decoherence times in the order of hundreds of µ s, comparable to high-purity homoepitaxial SCD. We quantify the effective crystal stress in different regions of the overgrown layer, indicating a low stress overall and a stress reduction in the diamond layer above the holes.