Direct observations of the geometry of defects in germanium

Transmission electron microscope studies of germanium deformed at strain rates that were large relative to the temperature of deformation showed the dislocations to be straight and aligned along <110> and <112> directions. All of the simple combinations of Burgers vector and line direction were encountered except two. Numerous T joins and elbows were found at which the line tensions were not balanced. Two types of dislocation dipole were found, namely pairs of dislocations aligned along <110> directions and pairs of dislocations aligned along <112> directions. The two types of dipole were equally numerous. Forty-five small angle boundaries were observed of which eleven were on (111) planes, thirteen were on (112) planes, eleven were on (110) planes, six were stepped and only four were curved. Sharp dislocation walls were formed even when the boundaries were not planar. The results are discussed in relation to geometrical models of dislocations in germanium and in terms of kink theories of dislocation movement. © 1963 Taylor & Francis Group, LLC.