Edge misfit dislocations in core–shell nanowire with surface/interface effects and different elastic constants

Abstract

A model of the generation for an edge misfit dislocation in the system of a nanowire surrounded by a co-axial film with surface/interface effects is investigated. The critical conditions of an edge misfit dislocation formation at the interface are analyzed, under considering the influence of the material elastic dissimilarity, misfit strains, the radius of the nanowire, core radius of the misfit dislocation and the surface/interface effects. The results show that the critical film thickness reduces with increment of the misfit strains, nanowire radius and core radius of the edge misfit dislocation, below the critical values of which, the misfit dislocation is energetically unfavorable whatever the film thickness. Critical film thickness first decreases and then increases with increasing the ratio of the shear modulus. There exists a critical film thickness below which no interfacial misfit dislocation could be introduced whatever the ratio of the shear modulus. There also exists a critical value of the ratio of the shear modulus, above which edge misfit dislocation does not form at any film thickness. The negative (positive) surface/interface stress can decrease (increase) the formation energy of the edge misfit dislocation. The positive (negative) surface/interface stress would increase (decrease) the critical film thickness, critical misfit strains and critical nanowire radius. The positive (negative) surface/interface stress would decrease (increase) the range of the film thickness and the critical ratio of the shear modulus. The larger the values of the surface/interface stress qualities, the greater the influence of the surface/interface stress on critical parameters.