  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.
