  Color centers in solid state crystals have become a frequently used system
for single photon generation, advancing the development of integrated photonic
devices for quantum optics and quantum communication applications. In
particular, defects hosted by two-dimensional (2D) hexagonal boron nitride
(hBN) are a promising candidate for next-generation single photon sources, due
to its chemical and thermal robustness and high brightness at room temperature.
The 2D crystal lattice of hBN allows for a high extraction efficiency and easy
integration into photonic circuits. Here we develop plasma etching techniques
with subsequent high temperature annealing to reliably create defects. We show
how different fabrication parameters influence the defect formation probability
and the emitter brightness. A full optical characterization reveals the higher
quality of the created quantum emitters, represented by a narrow spectrum,
short excited state lifetime and high single photon purity. We also
investigated the photostability on short and very long timescales. We utilize a
wet chemically-assisted transfer process to reliably transfer the single photon
sources onto arbitrary substrates, demonstrating the feasibility for the
integration into scalable photonic quantum information processing networks.
