Plasma treatments and photonic nanostructures for shallow nitrogen vacancy centers in diamond

TL;DR

This study examines how different plasma treatments affect the stability and photoluminescence of shallow nitrogen vacancy centers in diamond, demonstrating that certain plasma processes preserve NV$^-$ PL while others quench it.

Contribution

It introduces a low-damage 0V-bias plasma treatment method that maintains stable NV$^-$ PL in diamond nanostructures, advancing fabrication techniques for quantum applications.

Findings

Ar/SF$_6$/O$_2$ plasma quenches NV$^-$ PL

0V-bias and O$_2$ plasma preserve NV$^-$ PL

Nanopillar structures enhance photoluminescence detection

Abstract

We investigate the influence of plasma treatments, especially a 0V-bias, potentially low damage O$_2$ plasma as well as a biased Ar/SF$_6$/O$_2$ plasma on shallow, negative nitrogen vacancy (NV$^-$) centers. We ignite and sustain using our 0V-bias plasma using purely inductive coupling. To this end, we pre-treat surfaces of high purity chemical vapor deposited single-crystal diamond (SCD). Subsequently, we create $\sim$10 nm deep NV$^-$ centers via implantation and annealing. Onto the annealed SCD surface, we fabricate nanopillar structures that efficiently waveguide the photoluminescence (PL) of shallow NV$^-$. Characterizing single NV$^-$ inside these nanopillars, we find that the Ar/SF$_6$/O$_2$ plasma treatment quenches NV$^-$ PL even considering that the annealing and cleaning steps following ion implantation remove any surface termination. In contrast, for our 0V-bias as well as biased O$_2$ plasma, we observe stable NV$^-$ PL and low background fluorescence from the photonic nanostructures.