Photochromism of vacancy-related centres in diamond

Optical experiments, involving photoluminescence (PL), the PL excitation an d quenching spectra, as well as transmission and its quenching, were used t o analyse the photochromic behaviour of some vacancy-related complexes in d iamond. The 2.156 eV, 1.945 eV and 1.68 eV optical centres in CVD diamond a re attributed to the neutral nitrogen-vacancy, negative nitrogen-vacancy an d neutral silicon-vacancy ([Si-V](0)) centres, respectively. Oscillatory be haviour 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 su ggested for the ground state of the [Si-V](0) centre.