Nitrogen-Vacancy Centers in Epitaxial Laterally Overgrown Diamond: Towards Up-scaling of Color Center-based Quantum Technologies

TL;DR

This study demonstrates the growth of large-scale single-crystal diamond with native nitrogen-vacancy centers exhibiting long spin coherence times, advancing the scalability of diamond-based quantum technologies.

Contribution

It introduces a method for fabricating large-area SCD with native NV centers via heteroepitaxial lateral overgrowth, achieving high crystal quality suitable for quantum applications.

Findings

NV centers with spin-decoherence times of hundreds of microseconds

Low overall crystal strain in the overgrown layer

Reduced stress in regions above the holes

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 microseconds, comparable to high-purity homoepitaxial SCD. We quantify the effective crystal strain in different regions of the overgrown layer, indicating a low stress overall and a stress reduction in the diamond layer above the holes.