Techniques and products involving nanometer-scale structures, with dimensions ranging from 1 to 100 nanometers, especially those that transform matter, energy, and information using nanometer-scale components with precisely defined molecular features. In the late 1980s, the term nanotechnology entered widespread use to describe anticipated technologies based on the use of molecule-based machine systems designed to build complex products with atomic precision. Since the mid-1990s, usage has broadened to embrace instruments, processes, and products in which key dimensions are in the 1–100-nm range. Technologies that fit this definition are extremely diverse, but many could potentially contribute to the development of new products and processes such as advanced molecular manufacturing. Progress in nanotechnology can be judged by several metrics, including the increasing precision, complexity, cost-effectiveness, and scale of its products.
The corresponding long-term objectives are atomic precision, arbitrary complexity, low-cost production, and large-scale products. This combination of objectives appears feasible, but only through a multistage process starting with the more limited capabilities of current nanoscale technologies.
Nanoscale technologies are extremely diverse, rapidly changing, and often only tenuously connected. Products include nanoscale particles, fibers, and films of diverse materials and structures; nanoscale lithographic structures for electronics (many integrated circuits now qualify); structures formed by spontaneous molecular aggregation (selfassembly); and solids containing nanoscale grains or pores. The means and materials used to produce nanoscale and nanotextured structures often have little in common, and their applications range from stain-resistant clothing to state-of-the-art electronics.
Many nanotechnologies are a continuation of preexisting fields under a new label. What they share (particularly toward the lower end of the 1–100-nm range) is the emergence of novel properties, relative to the corresponding bulk materials, associated with surface and quantum effects, together with a distinctive set of instruments and computational modeling techniques. Grouping these diverse nanotechnologies together has fostered a vibrant crossfertilization of disciplines.
Looking forward, the metrics of complexity and scale define the chief frontiers. In small structures, precision has already reached the atomic limit. Examples include quantum dots, engineered biomolecular objects, self-assembled molecular structures, and sections of carbon nanotubes. For systems built with atomic precision, scale limits complexity. Great complexity is possible, even in nanosystems of microscopic scale. For example, a cubic micrometer of a typical material contains roughly 1011 atoms; with generalized atomic control on that scale, a cubic micrometer could contain roughly 109 distinct functional components.
Although complex systems with precise molecular features cannot be made with existing techniques, certain nanosystems can be designed and analyzed. Systems based on mechanical (rather than electronic) degrees of freedom are particularly tractable.
These are of special interest, because programmable nanoscale mechanical systems could be used to produce atomically precise structures of arbitrary complexity. The development of productive nanosystems is a key strategic objective.
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