Production of High Yield, Ultra-Shallow Nitrogen-Vacancy Centre Ensembles Through High Purity Forming gas Annealing

Abstract

Dense, ultra-shallow (<10 nm from the surface) ensembles of nitrogen-vacancy (NV) centers in diamond are sought-after for realising practical quantum sensing at the nanoscale. However, these ensembles typically suffer from reduced NV creation efficiency and spin coherence compared to their deeper and bulk counterparts. Consequently, most demonstrations in the literature to date have been restricted to using single NV centers with atypical coherence and charge stability properties not achievable across entire ensembles. In this work, we demonstrate that controlled annealing in a high purity forming gas atmosphere improves near-surface NV formation efficiency to over 20%. This environment pres..