Synchrotron Radiation White-Light Topographic Study Of Crystal Defects In Synthetic Diamond

Four groups diamonds synthesized under different conditions were studied using continuous spectra synchrotron radiation in this paper. The synthetic condition and process to reduce the crystal defects were researched through analyzed the growing course of crystal, and the calculation method of the crystallographic direction on the synchrotron topographs was brought forward.It was found that the characters of crystal defects of diamond synthesized under the same condition were similar and the characters of crystal defects of diamond synthesized under the different conditions were different through analyzed the synchrotron topographs of synthetic diamond.The space directions of crystal defects in four group samples were analyzed. The distributing characteristic of dislocations was that, the directions of dislocations in synthetic diamonds group A were main along <110> and <100>, the directions of dislocations in synthetic diamonds group B and group D were respectively along <110> and <100>. Layer disfigurement paralleling to the crystal surface of {111} were existed in specimen group A. The distributing characteristic of growth bands was that, the growth bands of group A were parallel to {110} and {100}, the growth bands of group B were parallel to {111}, and the growth bands of group C and group D were respectively parallel to {110} and {100}. The directions of dislocations were perpendicular to the directions of growth bands in group A and group D, and the directions of dislocations were not perpendicular to the directions of growth bands in group B. The growing course of crystal was researched through analyzed and calculated the defects of crystal. The sample group A was grown along {110} and {100}. The sample group B was grown along {111}. The sample group C was grown along {110}. The sample group D was grown along {100}.The main dislocations in synthetic diamond group A were originated from the surface of the seed crystal, and it was suggested the defects were main existed on the surface of seed crystal. So the dislocations exited on the surface of seed crystal were the main reason of the defects in synthetic diamond group A. The defects exited in the inner of crystal were brought because of the adulteration of impurity in growth course and the fluctuated of growth condition. The integrality of the synthetic diamond could be effectively enhanced and the defect density of synthetic diamond would be reduced if the defects on the surface of the seed crystal were reduced and the stabilization of growth condition was kept.