Dislocation structure of bulk AlN crystals under indentation

The results of cathodoluminescence studies of the defect structure created by indentation of the basic and prismatic surfaces of low-dislocation bulk crystals of aluminium nitride and gallium nitride are presented. It is found for the first time that the dislocation structure in the near-surface region at the indenter imprint in AlN is qualitatively different from that well known for other semiconductors with the wurtzite structure which is well explained by the Peierls model. It is concluded that this model is inapplicable for the characterisation of dislocations in AlN and that it is necessary to construct new theoretical approaches for this purpose.