  The integration of solid-state single-photon sources with foundry-compatible
photonic platforms is crucial for practical and scalable quantum photonic
applications. This study investigates aluminum nitride (AlN) as a material with
properties highly suitable for integrated on-chip photonics specifically due to
AlN capacity to host defect-center related single-photon emitters. We conduct a
comprehensive study of the creation and photophysical properties of
single-photon emitters in AlN utilizing Zirconium (Zr) and Krypton (Kr) heavy
ion implantation and thermal annealing techniques. Guided by theoretical
predictions, we assess the potential of Zr ions to create optically addressable
spin-defects and employ Kr ions as an alternative approach that targets lattice
defects without inducing chemical doping effects. With the 532 nm excitation
wavelength, we found that single-photon emitters induced by ion implantation
are primarily associated with vacancy-type defects in the AlN lattice for both
Zr and Kr ions. The emitter density increases with the ion fluence, and there
is an optimal value for the high density of emitters with low AlN background
fluorescence. Additionally, under shorter excitation wavelength of 405 nm,
Zr-implanted AlN exhibits isolated point-like emitters, which can be related to
Zr-based defect complexes. This study provides important insights into the
formation and properties of single-photon emitters in aluminum nitride induced
by heavy ion implantation, contributing to the advancement of the aluminum
nitride platform for on-chip quantum photonic applications.
