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

Simona Achilli, Nguyen H. Le, Guido Fratesi, Nicola Manini, Giovanni Onida, Marco Turchetti, Giorgio Ferrari, Takahiro Shinada, Takashi Tanii, Enrico Prati

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Special point defects in semiconductors have been envisioned as suitable components for quantum-information technology. The identification of new deep centers in silicon that can be easily activated and controlled is a main target of the research in the field. 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.

Original languageEnglish
Article number2011175
JournalAdvanced Functional Materials
Issue number21
Publication statusPublished - 2021 May 21


  • Ge-vacancy complex
  • Hubbard model
  • point defects
  • quantum transport
  • single-ion implantation


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