Luminescence of single color centers created in LiF crystals at low dose of irradiation

Color centers, found in lithium fluoride crystals grown in a reducing atmosphere and irradiated with a low dose of X-ray radiation, emit spectral luminescence band with maximum λmax = 800 nm and decay time constant of 26.5 ± 1 ns at room temperature. As the radiation dose increases, the concentration of these centers quickly saturates, while the concentrations of known intrinsic color centers continue to increase. This indicates the impurity nature of these color centers. The trajectories of the luminescence intensity and the decay time constants of single centers of this type were investigated. The luminescence is of flickering character. The temporal characteristics of the trajectories of luminescence intensity for different centers of the same type are different, while their decay time constants are the same. Similar pattern was revealed for the F2 color centers. These properties of single color centers in monocrystals are discussed.