Photochromism of vacancy-related centres in diamond

Optical experiments, involving photoluminescence (PL), the PL excitation and quenching spectra, as well as transmission and its quenching, were used to analyse the photochromic behaviour of some vacancy-related complexes in diamond. The 2.156 eV, 1.945 eV and 1.68 eV optical centres in CVD diamond are attributed to the neutral nitrogen-vacancy, negative nitrogen-vacancy and neutral silicon-vacancy ([Si-V](0)) centres, respectively. Oscillatory behaviour in the excitation spectrum of the 1.68 eV luminescence is observed and from the threshold of the oscillations a position of Ec - 2.05 eV is suggested for the ground state of the [Si-V](0) centre.