Photoluminescence of SiV centers in CVD diamond particles with specific crystallographic planes

We prepared the isolated micrometer-sized diamond particles without seeding on the substrate in hot filament chemical vapor deposition. The diamond particles with specific crystallographic planes and strong silicon-vacancy (SiV) photoluminescence (PL) have been prepared by adjusting the growth pressure. As the growth pressure increases from 2.5 to 3.5 kPa, the diamond particles transit from composite planes of 100 and 111 to only smooth 111 planes. The 111-faceted diamond particles present better crystal quality and stronger normalized intensity of SiV PL with a narrower bandwidth of 5 nm. Raman depth profiles show that the SiV centers are more likely to be formed on the near-surface areas of the diamond particles, which have poorer crystal quality and greater lattice stress than the inner areas. Complex lattice stress environment in the near-surface areas broadens the bandwidth of SiV PL peak. These results provide a feasible method to prepare diamond particles with specific crystallographic planes and stronger SiV PL.