Formation and properties of silicon vacancies in MPCVD-grown polycrystalline diamond

This study is aimed to have an understanding of the formation of silicon vacancy (SiV) colour centres in diamond during thin film growth of diamond in microwave plasma CVD reactor. The study focusses on different sources of silicon impurities in the chamber and the possibility of controlling the formation of SiV during growth for various applications. Diamond thin films were grown on different substrates and their photoluminescence (PL) spectra were analysed to understand the role of substrate material and residual silicon in the chamber for the formation of SiVs. The predominant contribution to SiV formation was found to be the residual silicon in the chamber originating from the quartz components exposed to the plasma. In the films grown on silicon substrate, there is also substrate contribution to the PL signal. Controlling the formation of SiVs in polycrystalline diamond can pave the way to optically integrate SiVs to different photonic structures.