Conservative climb of dislocations in crystals and its possible role in the processes of degradation of junction lasers

Abstract

The process of conservative climb of dislocations in a crystal lattice occurs through the pipe diffusion of lattice atoms along the dislocation core. It is proved in this paper that, if a dislocation circuit fulfils certain topological conditions, this process may give rise to unlimited growth of the dislocation length. Such a process is supposed to be realized in multilayer structures of junction lasers which suffer from a lattice mismatch between adjacent layers. It is demonstrated that, if a dislocation threads the active layer of the structure, a mass redistribution may occur in the layer by conservative climb of the dislocation during device operation, which leads to the development of dislocation dipoles and to a decrease in the level of internal strains. Features of this process and its relation to the phenomena of device degradation are discussed.