A cross-section taken through a thick chemically vapor-deposited polycrystalline diamond sample was studied by means of transmission electron microscopy. It was found that, in one region of the specimen, there was a {111} Σ = 3 twin boundary which was almost parallel to the plane of the section. This boundary, which contained the growth direction, exhibited a remarkable dislocation structure. This was analyzed by using diffraction contrast techniques and electron diffraction. It was concluded that these dislocations terminated monolayer steps on the grain boundary.

Observation of Monolayer Steps on {111}, Σ = 3 Twin Boundaries in Chemically Vapor-Deposited Polycrystalline Diamond. J.W.Steeds, A.E.Mora, J.E.Butler: Philosophical Magazine Letters, 2003, 83[5], 297-302