TY - JOUR
T1 - HR-TEM imaging and image simulation of vacancy clusters in brown diamond
AU - Barnes, R.
AU - Bangert, U.
AU - Martineau, P.
PY - 2006/9
Y1 - 2006/9
N2 - Diamonds, although famous for their sparkling colourless nature, can exhibit many colours due to imperfections in the crystal lattice. Brown diamonds, while not the favourite variety, have attracted much attention and mystery in finding the origin of the colour. The defect, which is not impurity related, can be removed with HPHT treatment. Collections of vacancies have been suggested as the source of the colour by theoretical calculations [1] and positron annihilation experiments [2, 3]. Therefore, simulations have been carried out to determine whether the suggested sizes of vacancy clusters could be seen in HR-TEM. Substantial contrast has been revealed in defocused images. In light of the simulations, experimental defocus series have been acquired in lattice resolution for brown and colourless, natural and synthetic type IIa diamonds. A small-scale patchiness is apparent in the lattice images of brown but not of colourless diamond. Further analysis, including simulations of multiple vacancy clusters, suggests this contrast in brown diamond could be due to many irregularly distributed vacancy clusters.
AB - Diamonds, although famous for their sparkling colourless nature, can exhibit many colours due to imperfections in the crystal lattice. Brown diamonds, while not the favourite variety, have attracted much attention and mystery in finding the origin of the colour. The defect, which is not impurity related, can be removed with HPHT treatment. Collections of vacancies have been suggested as the source of the colour by theoretical calculations [1] and positron annihilation experiments [2, 3]. Therefore, simulations have been carried out to determine whether the suggested sizes of vacancy clusters could be seen in HR-TEM. Substantial contrast has been revealed in defocused images. In light of the simulations, experimental defocus series have been acquired in lattice resolution for brown and colourless, natural and synthetic type IIa diamonds. A small-scale patchiness is apparent in the lattice images of brown but not of colourless diamond. Further analysis, including simulations of multiple vacancy clusters, suggests this contrast in brown diamond could be due to many irregularly distributed vacancy clusters.
UR - http://www.scopus.com/inward/record.url?scp=33749417069&partnerID=8YFLogxK
U2 - 10.1002/pssa.200671111
DO - 10.1002/pssa.200671111
M3 - Article
AN - SCOPUS:33749417069
SN - 1862-6300
VL - 203
SP - 3081
EP - 3087
JO - Physica Status Solidi (A) Applications and Materials Science
JF - Physica Status Solidi (A) Applications and Materials Science
IS - 12
ER -