Extended T2 times of shallow implanted NV in chemically mechanically polished diamond

Mechanical polishing of diamond is known to be detrimental to the spin lifetime and strain environment of near-surface defects. By utilising a chemical mechanical polishing (CMP) process, we demonstrate that we can achieve 13C-limited spin lifetimes of shallow implanted (<34 nm) NV centres in an industrially scalable process. We compare spin lifetimes (T2) of three diamonds processed with CMP with one processed by inductively-coupled plasma reactive ion etching (ICP-RIE), and observe an increased median T2 of 355 microseconds in the CMP-processed samples for 15NV centres implanted and annealed under identical conditions.