Misfit dislocations in nanowire heterostructures

The development of strain relaxation in lattice-mismatched semiconductor nanowire heterostructures is reviewed. Theoretical predictions for critical geometries for axial and core–shell structures are summarized and compared to experimental reports. All agree that nanowires can accommodate a greater elastic strain than is commonly seen with planar interfaces. Large mismatch as high as 10% has been elastically accommodated consistent with theoretical predictions. Elastically strained nanowire examples predominate, likely since nucleation is otherwise inhibited. A (maximum) critical radius is observed for epitaxial growth directly onto lattice-mismatched substrates. The few examples where strain relaxation via dislocations or roughening has been observed have been reported for core–shell geometries. This paper is dedicated to the late Professor Ulrich Gösele whose innovative leadership and insights in this field will not be forgotten .