Charge-State Tuning of Single SnV Centers in Diamond

Tin-vacancy (SnV) and other group-IV vacancy centers in diamond (SiV, GeV, and PbV) are intensively studied as promising alternatives to the nitrogen-vacancy (NV) center for quantum-based applications. The knowledge and the control of their charge state are therefore major issues. Here, using p-i-p planar junctions, we explore the charge states of implanted single SnV centers. We find two classes of centers, emitting either at 620 nm (SnV–) or at 646.8 nm but not both. We demonstrate the active and reversible tuning of individual SnV– centers. However, unlike the NV centers, which we tune reversibly and continuously between NV– (638 nm), NV0 (575 nm), and NV+ (dark) states, the two kinds of SnV centers do not tune from one to the other. These findings indicate that the 646.8 nm line is likely owing to another Sn-related defect rather than to the neutral charge state of the split vacancy SnV defect along the ⟨111⟩ axis. Furthermore, p-i-p structures can be used efficiently to induce a tunable band bending, stabilize SnV– and NV– states, and explore the charge-state transition energies of many defect centers.