Defect Formation in Two-Dimensional Carbon-Doped Hexagonal Boron Nitride

Tsz Wing Tang, Hongwei Liu, Yuyin Li, Jun Wang, and Zhengtang Luo<br/>¹Department of Chemical and Biological Engineering, the Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, P.R. China<br/><br/>Visible-range single photon emitters (SPEs) from monolayer hexagonal boron nitride has demonstrated exceptional optical performance as a candidate for quantum optical technology application. However, the controllability of the carbon defect engineering in hBN has remained elusive, including the unadjustable SPE density, unconfined wavelength, and low uniform yield. Thus, the integration into on-chip quantum devices has suffered. Here, by precisely controlling the carbon incorporation via diffusion from molten copper during chemical vapor deposition (CVD) growth, we demonstrate a strategy to engineer the defect density in hBN, and achieve high uniform SPEs with confined emission wavelengths in hBN. By controlling the carbon diffusion rate, we observed an increase in carbon doping level and provided evidence for achieving high-yield uniform single photon emitters in hBN down to monolayer limit. Our method enables the density of SPE creation to become adjustable, from hBN monolayer samples, with high uniformity and confined wavelength. This method stimulates a significant step forward to integrating advanced two-dimensional (2D) material engineering into on-chip quantum devices.<br/><br/><br/>The authors acknowledge the support from RGC (16304421).