Indexed on: 01 Sep '88Published on: 01 Sep '88Published in: Journal of Materials Science
Planar defects in layered GeSe and GeS crystals grown by vapour transport are studied by transmission electron microscopy. The principal defects are (110) twins, which appear as narrow parallel bands, and (001) low-angle grain boundaries, containing networks of boundary dislocations. In order to propose an atomistic model, the structure of the materials is described in terms of hexagonal rings and of trigonal pyramids projected along the c-axis. These units are used for the construction of the model of the twin structure which is free of dangling bonds. The relationship of the defects with the transport properties of the materials is discussed.