CRACK-LIKE SOURCES OF DISLOCATION NUCLEATION AND MULTIPLICATION IN THIN-FILMS

With the combination of the height sensitivity of atomic force microsc opy and the strain sensitivity of transmission electron microscopy, it is shown that near singular stress concentrations can develop natural ly in strained epitaxial films. These crack-like instabilities are ide ntified as the sources of dislocation nucleation and multiplication in films of high misfit. This link between morphological instability and dislocation nucleation provides a method for studying the basic micro mechanisms that determine the strength and mechanical properties of ma terials.