Modular design of locally ordered tetrahedral structures: III. Structural mechanism of nonequilibrium fibrous and rough-layer normal growth of diamond crystals

Abstract

Structural mechanisms of nontangential nonequilibrium normal growth of natural and synthetic diamond crystals with a fibrous or layered structure, formed under particularly nonequilibrium conditions, are proposed. It is shown that their growth is based on strained noncrystalline structures rapidly growing in length: 30/11 and 40/9 helices. The fibrous growth of diamond crystals along the 〈111〉 and 〈100〉 directions occurs according to the helicoidal mechanism, with helicoid axes in the form of 30/11 and 40/9 helices, respectively. Stacks of rough {110} lamellae can be formed via branching of 30/11 helices, which are then overgrown by a crystalline layer. Lamellae with orientation {100}, formed during the growth of diamond and silicon from vapor phase, also grow according to the helicoidal mechanism based on 40/9 helices via the aggregation of helicoids into these lamellae. Due to the complicated internal structure of these diamond crystals, their physical properties differ from those of diamond single crystals grown according to the tangential growth mechanism.