The low-angle [011] tilt boundary in germanium I. High-resolution structure determination

Abstract

Pure tilt boundaries (θ = 0·5 to 5°) in germanium bicrystals with a [011] common axis have been studied with respect to the tilt angle, θ, and the grain-boundary plane. Structural detail is revealed at a 3 Ä level by multi-beam interference using both a 100 and a 500 keV electron microscope. At this scale great complexity arises from dislocation splitting. Four types of grain boundaries are encountered : they are formed with dislocations having 1/2[011] Burgers vector, but also with very uncommon Burgers vectors such as [111] (split into three Frank dislocations) or 1/2[211] (split into three partials). The type of grain boundary is determined by both the tilt angle and the grain-boundary plane.