Charge-states modulation of nitrogen-vacancy (NV) centers incorporated into single crystal diamond films attracts increasing attention for solid-state qubits applications. Here, we discuss the electro- and photoluminescence emission properties of NV centers incorporated by gas phase nitrogen delta-doping of the intrinsic diamond layer of a positive-intrinsic-negative (PIN) junction diode. The experiments show that the charge state of NV centers can be intentionally controlled by applying well-defined external bias voltages. It can be switched from the negatively charged state NV− to the neutral charged state NV0 when a strong forward bias potential is applied. This can be switched back by application of reverse potentials. These results will be discussed assuming basic electronic properties of diamond PIN diodes, including the variation of spectral properties as well as the dynamics of charge state transitions.
In this Letter, the photoinduced switching of the single nitrogen-vacancy (NV) center between two different charge states, negative (${\mathrm{NV}}^{\ensuremath{-}}$) and neutral (
NV0), is studied under resonant excitation at liquid helium temperature. We show that resonant conversion of
NV0 to ${\mathrm{NV}}^{\ensuremath{-}}$ significantly improves spectral stability of the ${\mathrm{NV}}^{\ensuremath{-}}$ defect and allows high fidelity initialization of the spin qubit. Based on density functional theory calculations a novel mechanism involving an Auger ionization of ${\mathrm{NV}}^{\ensuremath{-}}$ and charge transfer of an electron from the valence band to
NV0 is discussed. This study provides further insight into the charge dynamics of the NV center, which is relevant for quantum information processing based on an ${\mathrm{NV}}^{\ensuremath{-}}$ defect in diamond.