TY - JOUR

T1 - The dislocation structure of diamond crystals grown on seeds in the Mg-C system

AU - Khokhryakov, Alexander F.

AU - Nechaev, Denis V.

AU - Palyanov, Yuri N.

AU - Kuper, Konstantin E.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - The dislocation structure of diamond crystals grown in the Mg-C system at a pressure of 7 GPa and temperatures of 1800–1900 °C is studied by X-ray topography and selective etching. According to the selective etching data, diamond crystals have two types of dislocations whose outputs on the {100} faces of crystal are associated with two types of etch pits. It has been demonstrated that the etch pits with the side wall inclination angle of about 7° are formed at the outcrop points of full edge dislocations, while the etch pits with the inclination angle of about 4° are associated with 45° mixed dislocations. It has been found that the dislocation structure of diamonds grown at 1900 °C is completely determined by the seed crystals structure and the dislocation density is 105 cm− 2. The dislocation density in the diamond crystals grown at 1800 °C increases by two or three orders of magnitude due to nucleation of dislocations at the seed-overgrown layer interface and in the overgrown layer. The high dislocation density leads to the mosaic structure of crystals and misorientation of single blocks, up to 1°. Local ring clusters of edge dislocations were found to be the dominant source of growth layers on the {100} faces of diamond.

AB - The dislocation structure of diamond crystals grown in the Mg-C system at a pressure of 7 GPa and temperatures of 1800–1900 °C is studied by X-ray topography and selective etching. According to the selective etching data, diamond crystals have two types of dislocations whose outputs on the {100} faces of crystal are associated with two types of etch pits. It has been demonstrated that the etch pits with the side wall inclination angle of about 7° are formed at the outcrop points of full edge dislocations, while the etch pits with the inclination angle of about 4° are associated with 45° mixed dislocations. It has been found that the dislocation structure of diamonds grown at 1900 °C is completely determined by the seed crystals structure and the dislocation density is 105 cm− 2. The dislocation density in the diamond crystals grown at 1800 °C increases by two or three orders of magnitude due to nucleation of dislocations at the seed-overgrown layer interface and in the overgrown layer. The high dislocation density leads to the mosaic structure of crystals and misorientation of single blocks, up to 1°. Local ring clusters of edge dislocations were found to be the dominant source of growth layers on the {100} faces of diamond.

KW - Dislocations

KW - Etching

KW - High pressure and high temperature

KW - Synthetic diamond

KW - X-ray topography

UR - http://www.scopus.com/inward/record.url?scp=84987875964&partnerID=8YFLogxK

U2 - 10.1016/j.diamond.2016.09.012

DO - 10.1016/j.diamond.2016.09.012

M3 - Article

AN - SCOPUS:84987875964

VL - 70

SP - 1

EP - 6

JO - Diamond and Related Materials

JF - Diamond and Related Materials

SN - 0925-9635

ER -