Nanoscale Dislocation Patterning in PbTe/PbSe(001) Lattice-Mismatched Heteroepitaxy

Dislocation patterning in PbTe on PbSe (001) heteroepitaxy is studied using scanning tunneling microscopy. It is shown that exceedingly regular square arrays of misfit dislocations are formed during strain relaxation. This is based on the existence of a homogeneous dislocation nucleation process, a high dislocation mobility within the interface, and an effective repulsive interaction between neighboring dislocations. Similar results are expected also for other highly mismatched heteroepitaxial systems.