Charge dynamics in near-surface, variable-density ensembles of nitrogen-vacancy centers in diamond

TL;DR

This study investigates the charge conversion dynamics of near-surface nitrogen-vacancy centers in diamond, revealing defect-induced rates, single-photon processes, and potential for data storage and biosensing applications.

Contribution

It uncovers the charge dynamics of shallow NV centers affected by high-density ion implantation and demonstrates rewritable patterning for sensing and data storage.

Findings

Charge conversion rates increase linearly with laser intensity.

Charge transfer to traps occurs in the dark.

Rewritable NV patterns can be imprinted over large areas.

Abstract

Although the spin properties of superficial shallow nitrogen-vacancy (NV) centers have been the subject of extensive scrutiny, considerably less attention has been devoted to studying the dynamics of NV charge conversion near the diamond surface. Using multi-color confocal microscopy, here we show that near-surface point defects arising from high-density ion implantation dramatically increase the ionization and recombination rates of shallow NVs compared to those in bulk diamond. Further, we find that these rates grow linearly not quadratically with laser intensity, indicative of single-photon processes enabled by NV state mixing with other defect states. Accompanying these findings we observe NV ionization and recombination in the dark, likely the result of charge transfer to neighboring traps. In spite of the altered charge dynamics, we show one can imprint rewritable, long-lasting patterns of charged-initialized, near-surface NVs over large areas, an ability that could be exploited for electrochemical biosensing or to optically store digital data sets with sub-diffraction resolution.