Photoluminescence of silicon‐vacancy defects in nanodiamonds of different chondrites |
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| Authors: | A A Shiryaev A V Fisenko L F Semjonova A A Khomich I I Vlasov |
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| Institution: | 1. Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia;2. Institute of Ore Deposits, Petrography, Geochemistry and Mineralogy RAS, Moscow, Russia;3. Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow, Russia;4. General Physics Institute RAS, Moscow, Russia;5. National Research Nuclear University MEPhI, Moscow, Russia |
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| Abstract: | Photoluminescence spectra show that silicon impurity is present in lattice of some nanodiamond grains (ND) of various chondrites as a silicon‐vacancy (SiV) defect. The relative intensity of the SiV band in the diamond‐rich separates depends on chemical composition of meteorites and on size of ND grains. The strongest signal is found for the size separates enriched in small grains; thus, confirming our earlier conclusion that the SiV defects preferentially reside in the smallest (≤2 nm) grains. The difference in relative intensities of the SiV luminescence in the diamond‐rich separates of individual meteorites are due to variable conditions of thermal metamorphism of their parent bodies and/or uneven sampling of nanodiamond populations. Annealing of separates in air eliminates surface sp2‐carbon; consequently, the SiV luminescence is enhanced. Strong and well‐defined luminescence and absorption of the SiV defect is a promising feature to locate cold (<250 °C) nanodiamonds in space. |
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