Abstract

This talk will introduce the new science of atomic structure of nanomaterials and their significance to our new understanding about properties and growth of these materials. Nanotubes and metallic nanoclusters will be used as examples of study. Nanotubes, in particular of single wall carbon nanotubes, have been one of major focus areas of nanoscience and nanotechnology research because of their remarkable electrical and mechanic properties. However, the electric properties of carbon nanotubes (CNT) are very sensitive to small structural differences. Metallic nanoclusters are important catalyst for energy and environmental applications. The atomic structure of metal clusters can be very different from bulk crystals. Information mostly comes from HREM . Consequently, our understanding of these structures is subjected to the limitations of atomic resolution imaging. Recently, we have developed a new electron diffraction technique, nanoarea electron diffraction (NED), which is capable of structure determination of individual nanotubes and clusters using a nanometer-sized, coherent, parallel electron beam. We will illustrate the potential of this technique for atomic structure determination. The talk is divided into three parts. The first part will cover structure determination of single and double wall carbon and multiwall boron nitride nanotubes. The second part will focus on our efforts to obtain atomic resolution images from coherent diffraction patterns and its potential to image defects in individual nanoclusters. The last part of this talk highlights other materials science problems that can be addressed by NED .