Structural imperfections associated with supersaturated vacancies in an HPHT-grown diamond single crystal

A diamond single crystal, which was synthesized at a high temperature of 15 70 K and a high pressure of 5.5 GPa in a Fe-Ni-C system, was directly and s ystematically examined by transmission electron microscopy (TEM). It is pro posed that there exists a variety of imperfections such as dislocation loop s, stacking faults, twins and stacking-fault tetrahedral in the diamond, wh ich may be derived from the supersaturated vacancies generated during rapid cooling from high temperature. The formation process of the imperfections is discussed briefly.