Unzipping and movement of Lomer-type edge dislocations in Ge/GeSi/Si(0Â 0Â 1) heterostructures

Edge dislocations in face-centered crystals are formed from two mixed dislocations gliding along intersecting {1 −1 1}  planes, forming the so-called Lomer locks. This process, which is called zipping, is energetically beneficial. It is experimentally demonstrated in this paper that a reverse process may occur in Ge/GeSi strained buffer/Si(0 0 1) heterostructures under certain conditions, namely, decoupling of two 60° dislocations that formed the Lomer-type dislocation, i.e., unzipping. It is assumed that the driving force responsible for separation of Lomer dislocations into two 60° dislocations is the strain remaining in the GeSi buffer layer.