Synthesis of hexagonal boron nitrides by chemical vapor deposition and their use as single photon emitters

Two-dimensional (2D) hexagonal boron nitride (hBN), due to its extraordinary thermal, chemical, and optical properties, has arisen as an enticing material for the research community to explore for various applications, including the use of site defects in hBN as single photon emitters (SPEs). In this review, we systematically summarize recent advanced strategies towards the controllable synthesis of 2D hBN using chemical vapor deposition, towards a full control of the domain size, orientation, morphology, layer number, and stacking order, etc. Moreover, we review the underlying mechanisms for single photon emission (SPE) in hBN and methods to selectively generate and tune the SPEs. Defects (e.g., carbon substituted defects) are discussed for the potential use as emission sites. We finally give an outlook of future challenges and opportunities on desirable hBN synthesis and further investigation of SPEs in hBN, targeting to utilize hBN as single photon emitters in an industrial scale.