  Hexagonal boron nitride (hBN) is an emerging two dimensional material for
quantum photonics owing to its large bandgap and hyperbolic properties. Here we
report a broad range of multicolor room temperature single photon emissions
across the visible and the near infrared spectral ranges from point defects in
hBN multilayers. We show that the emitters can be categorized into two general
groups, but most likely possess similar crystallographic structure. We further
show two approaches for engineering of the emitters using either electron beam
irradiation or annealing, and characterize their photophysical properties. The
emitters exhibit narrow line widths of sub 10 nm at room temperature, and a
short excited state lifetime with high brightness. Remarkably, the emitters are
extremely robust and withstand aggressive annealing treatments in oxidizing and
reducing environments. Our results constitute the first step towards
deterministic engineering of single emitters in 2D materials and hold great
promise for the use of defects in boron nitride as sources for quantum
information processing and nanophotonics.
