Imaging Extended Defects by TEM

In this invited talk, I will suggest where we are in our use of TEM for imaging extended defects and guess where we are going. Since the topic of this Symposium concerns advances in imaging and quantification of strain, local atomic structure, and the chemistry of extended defects, the present talk will emphasize the history and development of diffraction contrast methods for the analysis of extended defects in the TEM but must also include a discussion of the use of high-resolution imaging techniques. Examples will be presented from my group’s work on metals, semiconductors and ceramics with a discussion of the factors that have limited our understanding of these defects and those that continue to limit our ability to improve this understanding.