Center for Functional Nanomaterials Seminar

The promise of nanoscience lies in the fact that nanomaterials can show distinct physical properties that are not simply scaled-down bulk characteristics. Transmission electron microscopy (TEM), providing the necessary spatial resolution to observe individual nanostructures and follow their behavior over a wide range of conditions, is uniquely suited to study the physics governing nanomaterials growth and processing.

Here, we discuss examples of the application of high temperature TEM to understanding the distinct properties of nanomaterials. We observe and quantify the phase behavior of nanometer-scale objects, which – although believed to differ significantly from that in the bulk – has remained poorly understood to date. Our results include the identification of size effects on the phase diagram of binary alloys, which are key to understanding and controlling the synthesis and doping of semiconductor nanowires. Using the same approach, we explore the formation of heterostructures by encapsulating semiconductor nanowires in ordered graphene shells. We demonstrate the use of these graphene shells as nano-mechanical actuators for fluid manipulation at the ultimate size limit.