Nickel doping of nitrogen enriched CVD-diamond for the production of single photon emitters

Chemical vapour deposition has been utilised for the fabrication of nickel-nitrogen defects in diamond. By introducing nickel, as well as nitrogen into the process gas, this approach offers the advantage, that a direct formation of nickel-nitrogen centres on the growing surface is possible. This could therefore make postannealing steps superfluous. Nanocrystalline diamond films, as well as single crystal layers were grown under addition of nickel and nitrogen using different doping sources, namely: gaseous nickelocene, nickel powder and nickel wire. The amount of nickel present in the gas phase was characterised by optical emission spectroscopy (OES). In order to investigate the presence of nickel or nickel-nitrogen-related defects, photoluminescence (PL) measurements at different temperatures have been applied. A strong fluorescence in the range between 800 and 900 nm, accompanied by a peak at around 817 nm, as well as a narrow peak at 788 nm has been observed at cryogenic temperatures (10 K). The peak at 788 nm indicates the presence of nickel and nickel-nitrogen-related complexes in our samples. PL measurements at higher temperatures reveal, an initially rising intensity of a broad emission band at temperatures up to 200 K, while the emission is quenched at 300 K.