Luminescence of natural diamond in the NIR range

Abstract

Natural diamond remains the source of many interesting effects and finds that are difficult to reproduce or detect in synthetic crystals. Herein, we investigate the photoluminescence (PL) of more than 2000 natural diamonds in the range 800–1050 nm. PL spectra were registered with excitation at 405, 450, 488 (Ar+), and 787 nm. The investigation revealed several systems that were not previously described. Some new dislocation-related systems were discovered in the spectra of crystals with signs of plastic deformation. They are four sets of doublets 890/900.3 nm, 918/930 nm, 946.5/961.5 nm, and 981/994 nm; four lines at 946, 961.5, 986, and 1020 nm. In low-nitrogen diamonds, they are accompanied by a line at 921 nm. Unreported vibronic systems with zero-phonon lines at 799.5, 819.6, 869.5, and 930 nm were revealed. In most cases, the systems were accompanied with doublet 883/885 of the simplest Ni-related center. We assigned these systems to Ni-related centers of different complexity. The results expand opportunities to restore growth conditions and thermal history of diamond crystals. The detection of new shallow centers expands the prospects of diamond as an optic and semiconductor material for applications in the NIR range.