Size-reduction of nanodiamonds via air oxidation
  Here we report the size reduction and effects on nitrogen-vacancy centres in nanodiamonds by air oxidation using a combined atomic force and confocal microscope. The average height reduction of individual crystals as measured by atomic force microscopy was 10.6 nm/h at 600 {\deg}C air oxidation at atmospheric pressure. The oxidation process modified the surface including removal of non-diamond carbon and organic material which also led to a decrease in background fluorescence. During the course of the nanodiamond size reduction, we observed the annihilation of nitrogen-vacancy centres which provided important insight into the formation of colour centres in small crystals. In these unirradiated samples, the smallest nanodiamond still hosting a stable nitrogen-vacancy centre observed was 8 nm. 
T. Gaebel (1), C. Bradac (1), J. Chen (2), P. Hemmer (2), and J.R.   Rabeau (1) ((1) ARC Centre of Excellence for Engineered...
cond-mat.mes-hall quant-ph