  Quantum light sources are crucial foundational components for various quantum
technology applications. With the rapid development of quantum technology,
there has been a growing demand for materials with the capability of hosting
quantum emitters. One such material platform uses fluorescent defects in
hexagonal boron nitride (hBN) that can host deep sublevels within the bandgap.
The localized electron irradiation has shown its effectiveness in generating
deep sublevels to induce single emitters in hBN. The question is whether
localized (electron beam) irradiation is a reliable tool for creating emitters
in other wide bandgap materials and its uniqueness to hBN. Here, we investigate
and compare the fabrication of quantum emitters in hBN and exfoliated muscovite
mica flakes along with other 3D crystals, such as silicon carbide and gallium
nitride, which are known to host quantum emitters. We used our primary
fabrication technique of localized electron irradiation using a standard
scanning electron microscope. To complement our experimental work, we employed
density functional theory simulations to study the atomic structures of defects
in mica. While our fabrication technique allows one to create hBN quantum
emitters with a high yield and high single photon purity, it is unable to
fabricate single emitters in the other solid-state crystals under
investigation. This allows us to draw conclusions on the emitter fabrication
mechanism in hBN, which could rely on activating pre-existing defects by charge
state manipulation. Therefore, we provide an essential step toward the
identification of hBN emitters and their formation process.
