Photon emission enhancement of lanthanoid ions implanted in gallium nitride nanostructures

Reliable single-photon sources (SPSs) that provide on-demand single photons are indispensable in the rapidly growing field of quantum technologies. To be maximally useful, they must operate at room temperature, be compatible with mature fabrication processes, and integrate seamlessly with other photonic systems. These requirements have driven research into gallium nitride (GaN)-based photon emitters and devices. Lanthanoid (Ln)-doped GaN exhibits temperature-insensitive, spectrally sharp, and stable visible/near infrared emission. Additionally, Ln-doped GaN leverages a well-developed GaN platform, enabling integration into more complex devices. However, the spontaneous emission rate of Ln ions in the 4f-4f transition is lower than that of other SPS candidates, such as quantum dots. In this study, we present two types of nanostructures that enhance the photon emission of implanted Ln ions in GaN: nanopillar structures and photonic crystal nanocavities. We discuss the mechanisms by which these nanostructures enhance photon emission and explore the future prospects of Ln-doped GaN SPS.