Formation yield of germanium-vacancy centers in diamond upon keV ion nano-implantation and thermal annealing

Group-IV-related color centers in diamond are promising systems in the framework of solid-state quantum technologies. A key enabler for the integration of these emitters in real-world devices consists of their reliable fabrication by means of controlled engineering processes such as deterministic ion implantation. In this work, the formation yield of the negatively charged germanium-vacancy (GeV−) center in diamond upon keV ion implantation and subsequent thermal annealing was investigated. A systematic fabrication approach was adopted, exploiting focused ion beam technology to take advantage of nanometric spatial accuracy and a controllable implantation fluence. The photoluminescence analysis of the implanted spots, including single emitter characterization, enables the direct quantification of the GeV− center formation yield under the implemented fabrication approach.