Nanoscale science and technology is a young and burgeoning field that encompasses nearly every discipline of science and engineering. With rapid advances in areas such as molecular electronics, synthetic biomolecular motors, DNA-based self-assembly, and manipulation of individual atoms via a scanning tunneling microscope, nanotechnology has become the principal focus of a growing cadre of scientists and engineers and has captured the attention and imagination of the general public. This field is defined primarily by a unit of length, the nanometer (1 nm = 10 ^-9 m), at which lies the ultimate control over the form and function of matter. Indeed, since the types of atoms and their fundamental properties are limited by the laws of quantum physics, the smallest scale at which we have the freedom to exercise our creativity is in the combination of different numbers and types of atoms used to fabricate new forms of matter. This is the arena of nanotechnology: to build materials and devices with control down to the level of individual atoms and molecules. Such capabilities result in properties and performance far superior to conventional technologies and, in some cases, allow access to entirely new phenomena only available at such scales.

The rapid growth of the field in the past two decades has been enabled by the sustained advances in the fabrication and characterization of increasingly smaller structures. Section I provides an overview of such enabling technologies. The fabrication side has seen the emergence of two paradigms, respectively referred as "top-down"...