A low angle twist boundary formed by bonding an ultra-thin (001) Si film onto a (001) Si wafer was investigated using two-beam transmission electron microscopy to identify positively zigzag lines which separate large interfacial regions formed by square networks of ½<110> screw misfit dislocations. An approach to the elastic field of a zigzag line was proposed from the repetitive use of angular dislocations added to a ribbon-like uniform distribution of infinitesimal dislocations parallel to a family of pure screw misfit dislocations. Theoretical and experimental images of successive triple nodes were compared to derive the unique set of Burgers vectors attached to a zigzag line. In principle, this approach could be applied to any elongated hexagonal mesh of a dislocation network.

Zigzag Lines in a (001)Si Low-Angle Twist Boundary. A.Boussaid, M.Fnaiech, F.Fournel, R.Bonnet: Philosophical Magazine, 2005, 85[11], 1111-22