Chemical control of the charge state of nitrogen-vacancy centers in diamond

TL;DR

This study demonstrates that surface termination of diamond with hydrogen can convert nitrogen-vacancy centers from negatively charged to neutral or non-fluorescent states, enabling chemical and electrostatic control of their charge states.

Contribution

It reveals how hydrogen surface termination influences NV center charge states and introduces a method for chemical and electrostatic charge state control in diamond.

Findings

Hydrogen termination converts NV- to NV0 and non-fluorescent states.

Surface band bending causes electron depletion near NV centers.

Hydrogen termination enables chemical and electrostatic charge control.

Abstract

We investigate the effect of surface termination on the charge state of nitrogen vacancy centers, which have been ion-implanted few nanometers below the surface of diamond. We find that, when changing the surface termination from oxygen to hydrogen, previously stable NV- centers convert into NV0 and, subsequently, into an unknown non-fluorescent state. This effect is found to depend strongly on the implantation dose. Simulations of the electronic band structure confirm the dissappearance of NV- in the vicinity of the hydrogen-terminated surface. The band bending, which induces a p-type surface conductive layer leads to a depletion of electrons in the nitrogen vacancies close to the surface. Therefore, hydrogen surface termination provides a chemical way for the control of the charge state of nitrogen-vacancy centers in diamond. Furthermore, it opens the way to an electrostatic control of the charge state with the use of an external gate electrode.