Photoluminescence study on the optical properties of silicon-vacancy centre in diamond

The optical properties of a silicon-vacancy (Si–V) centre were studied using photoluminescence (PL), including the temperature (80 K–270 K) and excitation power (2.25 W-22.5 mW)-dependent PL measurements and the effect of electron irradiation on the PL signal. The intensity decrease, red shift, and broadening of the line width with increasing temperature were fitted nonlinearly. The thermal quenching activation energy (49.59 meV), Huang-Rhys factor (0.049), and average phonon energy (42.09 meV) of the Si–V centre were obtained using suitable physical formulas. For the excitation power dependence, only the PL intensity of Si–V centre was sub-linear with the increasing power, the radiative recombination was dominated and the impact of Auger recombination was negligible. In addition, Fermi level shifted below the ground state level of Si–V in irradiation region due to the introduction of neutral single vacancy (GR1) centre, the PL signal of the Si–V centre was suppressed.