Position‐Controlled Functionalization of Vacancies in Silicon by Single‐Ion Implanted Germanium Atoms

Vacancy‐related complexes are suitable to provide deep electronic levels but they are hard to control spatially. With the spirit of investigating solid state devices with intentional vacancy‐related defects at controlled position, the functionalization of silicon vacancies is reported on here by implanting Ge atoms through single‐ion implantation, producing Ge‐vacancy (GeV) complexes. The quantum transport through an array of GeV complexes in a silicon‐based transistor is investigated. By exploiting a model based on an extended Hubbard Hamiltonian derived from ab initio results, anomalous activation energy values of the thermally activated conductance of both quasi‐localized and delocalized many‐body states are obtained, compared to conventional dopants. Such states are identified, forming the upper Hubbard band, as responsible for the experimental sub‐threshold transport across the transistor. The combination of the model with the single‐ion implantation method enables future research for the engineering of GeV complexes toward the creation of spatially controllable individual defects in silicon for applications in quantum information technology.