Easy Nitrogen Vacancy Ion Engineering using Focused Ion Beams – ENVIE-FIB

We will design and optimize a FIB column which will allow us to implant nitrogen atoms inside an ultrapure diamond sample. After annealing, these impurities embedded in the crystal lattice will be transformed into NV color centers.
The ion column is being tested at Orsay Physics to optimize the focusing of the beam with acurrent of the ion beam that will be compatible with the creation of single NV centers. The resolution of the implantation process will be measured independently by a super-resolved optical microscopy technique previously developed at the Aimé Cotton laboratory.
The vacuum chamber and all scanning devices for the sample positioning have been designed. The chamber will integrate the ion column with an independent electron column that will display with a a very high resolution the area of the sample over which the ion beam is focused.

1) An ion column was developed at ORSAY PHYSICS in order to combine the optics for focusing the ion beam with a photonics microscope that gives an image of the spot on which the ions are focused. Preliminary characterizations demonstrated a resolution of nearly 30 nm in the image that was recorded by detecting the secondary electrons produced by the focused ions on a test sample.
2) A vacuum chamber allowing us to combine the ion column with an electron microscope column has been designed at laboratory Aime Cotton. the setup integrates several nanopositioning elements. Part of this system is currently being manufactured.

The project will establish an implementation platform which performances will exceed the state of the art:
- the resolution reached by the focusing of the ion beam will allow us to engineer NV centers with nanometer accuracy;
- By combining the implantation ion beam with an electron beam generated by a Schottky source, we will be able to visualize and address single microstructures and even single nanostructures for implantation.

The possibility of patenting two technical innovations is under investigation.

The ENVIE-FIB proposal aims at exploiting the unique physical properties of NV color centres in ultrapure single-crystal CVD-grown diamond to develop innovative quantum-based devices with unprecedented performances, especially an efficient single-photon source. The consortium gathers the group of Jean-Francois Roch and Vincent Jacques in Laboratoire Aime Cotton, experts in the physics and the applications of NV centers, with Orsay Physics.

ENVIE-FIB will build a combined instrument based on the i-FIB ion column developed by Orsay Physics and which is based on a ECR gas source adapted to xenon and nitrogen molecules. Nitrogen will be used to create NV centers by shallow ion implantation, with the goal to achieve 10-nm resolution in the positioning of the NV center. Xenon will be used to mill the diamond layer, in order to overcome the limitation due to the high index of refraction of diamond. We will elaborate a solid immersion lens (SIL) above the NV center which will lead to an enhancement of the excitation and detection of the coupled single NV centers by approximately one order of magnitude.

The ion column will be associated to on-line optical microscope which will give an in situ image of the implantation area. The chamber will be designated to integrate a scanning electron microscope which will provide a live observation of the milling process. The electron image could also allow the implantation of nitrogen in photonics nanostructures associated to high-efficiency single-photon sources, such as photonic crystals and micropillars.

In conclusion, ENVIE-FIB aims at integrating the efforts of the the two partners in order to develop a technology for the controlled fabrication of NV centers and their coupling to microstructures. The instrument delivered in the project will push further the limits of the promising NV-based technologies.