Low-Background Single-Photon Emission and Multiwavelength Electroluminescence from Carbon-Doped Hexagonal Boron Nitride

Single-photon emitters (SPEs) in two-dimensional materials hold significant promise for scalable quantum technologies. Hexagonal boron nitride (hBN) has attracted significant attention owing to its high chemical stability and outstanding photon extraction efficiency. However, achieving controllable defect engineering and electrical excitation of SPEs in hBN remains a critical challenge. Here, we propose a carbon-doping strategy to enable the controlled generation of high-density SPEs in hBN. By combining high-temperature carbon doping with subsequent air annealing, we achieved room-temperature single-photon emission spanning 1.7–2.5 eV while effectively suppressing background emission. Furthermore, we fabricated a van der Waals (vdW) heterojunction device using carbon-doped hBN (hBN:C). Numerous low-background electrically driven spike emissions were observed at 78 K, ranging from 1.7 to 3.1 eV, with a most narrow line width of 1.66 meV. Our findings provide a promising pathway for integrating hBN defects into compact single-photon devices for on-chip quantum applications.