Germanium vacancy centre formation in CVD nanocrystalline diamond using a solid dopant source

We report the in-situ formation of germanium vacancy (GeV) centres in nanocrystalline diamond (NCD) using chemical vapor deposition (CVD) technique. Commercial Ge wafers are used as the solid dopant source and as substrate. The hydrogen-rich plasma (1% CH4 in H2, 3000 W and 45 Torr, ASTeX 6500 series deposition system) etches the Ge substrate and introduces the GeV complex in the NCD layer. As the melting proximity of Ge and CVD diamond growth temperature introduces limitations; the NCD depositions are restricted to (720 ± 20)°C. Scanning electron microscopy reveal randomly facetted film morphology and Raman measurements confirm diamond formation under the chosen deposition conditions.