Low temperature investigations of single silicon vacancy colour centres in diamond

We study single silicon vacancy (SiV) centres in chemical vapour deposition (CVD) nanodiamonds on iridium as well as an ensemble of SiV centres in a high quality, low stress CVD diamond film by using temperature dependent luminescence spectroscopy in the temperature range 5-295 K. We investigate in detail the temperature dependent fine structure of the zero-phonon-line (ZPL) of the SiV centres. The ZPL transition is affected by inhomogeneous as well as temperature dependent homogeneous broadening and blue shifts by about 20 cm-1 upon cooling from room temperature to 5 K. We employ excitation power dependent g(2) measurements to explore the temperature dependent internal population dynamics of single SiV centres and infer almost temperature independent dynamics.