Dislocation Mechanisms of Misfit Stress Relaxation in Crystalline Nanoheterostructures

A brief review of theoretical models describing the dislocation mechanisms of misfit stress relaxation in crystalline nanoheterostructures of lower dimension, such as composite nanoparticles, nanowires, and nanolayers is presented. The critical conditions for the appearance of the first misfit dislocations in such nanoheterostructures are determined. The equilibrium distribution density was calculated for the circular prismatic loops of misfit dislocations in core–shell nanowires and proved to be in good agreement with the results of experimental observations. Energy barriers have been found for the nucleation of misfit dislocations in composite nanowires with a core shaped as a rectangular prism and in composite nanolayers with long prismatic inclusions. The lowest barriers are shown to occur upon the emission of partial or perfect dislocation dipoles by the edges of inclusions, depending on the characteristic dimensions of a heterostructure. The directions of further studies in this area were proposed.