CATHODOLUMINESCENCE OF BROWN DIAMONDS AS OBSERVED BY TRANSMISSION ELECTRON-MICROSCOPY

Cathodoluminescing features in brown diamonds correlate with the crystalline microstructure as observed by transmission electron microscopy. We identified distinctive emissions at 415.3, 425, 491.3 and 525 nm. The first two correlate with the so-called N3 and band-A emissions, while the last correlates with what is called a strain-broadened H3 band. The N3 emission is associated with stacking faults on {111} planes. H3 emission is correlated with straight dislocations and dislocation tangles. The 491.3 nm and H3 emissions suggest that the diamonds have undergone severe plastic deformation, which may have also contributed to the apparent high concentrations of the N3 defects.