Lateral dimensions are as small as 180 nanometers for the critical gate length, and semiconductor industry roadmaps call for them to get even smaller. The manufacture of silicon transistors already requires the controlled deposition of layered structures just a few atoms thick (about 1 nanometer). Nanostructured materials are in wide use in information technology, integrated into complex products such as the hard disk drives that store information and the silicon integrated circuit chips that process information in every Internet server and personal computer. More recently, more sophisticated uses of nanoscale materials have been realized. Nanostructured cemented carbide coatings are used on some Navy ships for their increased durability. Nanostructured wear-resistant coatings for cutting tools and wear-resistant components have been in use for several years. Paints with reflective properties are also being manufactured using nanoscale titanium dioxide particles. Nanoscale iron oxide powder is now being used as a base material for rouge and lipstick. For example, nanoscale titanium dioxide and zinc oxide powders are now commonly used by cosmetics manufacturers for facial base creams and sunscreen lotions. The earliest application of nanoscale materials occurred in systems where nanoscale powders could be used in their free form, without consolidation or blending. PRESENT APPLICATIONS OF NANOSCALE MATERIALS AND PHENOMENA Some of the current impacts, as well as anticipated longer-term impacts, of the technical revolution that will be ushered in by nanoscale science and technology are discussed in more detail below. Figure 1.2 is a time line for anticipated impacts. Beyond any speculation or hype, the committee can point to current applications of nanoscale materials and to devices that are already impacting our nation's commerce, as well as advances that are mature enough to promise impacts in the near future. Many potential applications of nanoscale science and technology have been touted in both the scientific and the popular press, and there has been no shortage of promises made for the ability of nanoscale technology to revolutionize life as we know it. The National Nanotechnology Initiative (NNI) was established primarily because nanoscale science and technology are predicted to have an enormous potential economic impact. Courtesy of Office of Basic Energy Sciences, Office of Science, U.S. The size of nanoscale objects and phenomena compared with the size of small everyday objects. Nanoscale science and engineering also seek to discover, describe, and manipulate those unique properties of matter at the nanoscale in order to develop new capabilities with potential applications across all fields of science, engineering, technology, and medicine. Furthermore, carbon nanotubes conduct electricity in only one spatial dimension, that is, along one axis, rather than in three dimensions, as is the case for graphite. For example, carbon nanotubes are much less chemically reactive than carbon atoms and combine the characteristics of the two naturally occurring bulk forms of carbon, strength (diamond) and electrical conductivity (graphite). This capability has led to the astonishing discovery that clusters of small numbers of atoms or molecules-nanoscale clusters-often have properties (such as strength, electrical resistivity and conductivity, and optical absorption) that are significantly different from the properties of the same matter at either the single-molecule scale or the bulk scale. In the last two decades, researchers began developing the ability to manipulate matter at the level of single atoms and small groups of atoms and to characterize the properties of materials and systems at that scale. Figure 1.1 provides some sense of how this scale relates to more familiar, everyday scales. Nanoscale science and technology, often spoken of as “nanoscience” or “nanotechnology,” are simply science and engineering carried out on the nanometer scale, that is, 10 −9 meters.
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