DIAMOND CRYSTAL WITH Y-DEFECTS: SPECTROSCOPY AND TRANSMISSION ELECTRON MICROSCOPY

The paper presents results of investigation of a natural Ib-IaA diamond containing Y-defects from Yubileinaya kimberlite pipe, Yakutia. Analysis of spatial distribution of nitrogen-related A- and C-centers and intensity of infrared (IR) absorption at Raman frequency (1332 cm–1) reveals anticorrelation between these defects. Transmission electron microscopy of a zone with abundant Y-defects shows presence of dislocations in various configurations and numerous clusters of point defects generated by non-conservative dislocation movement. Extended defects with shape resembling thin (1–3 nm) rhombic plates with the largest dimension up to 5–20 nm are observed. Analysis of contrast of these defects shows that they represent nanosized voids (vacancy clusters). It is suggested that the defects were formed by annihilation of dislocation dipoles with subsequent growth by consumption of vacancies produced by non-conservative motion of dislocations. Upon excitation by 787 nm laser, numerous narrow photoluminescence lines are observed between 800–900 nm, their intensity and position show pronounced spatial heterogeneity on scale of few microns. Qualitatively similar behavior was earlier noted for hydrogenated nanodiamonds. It is suggested that the unusual behavior of the luminescence lines may be explained by recombination processes on internal walls of the discovered nanovoids.