What is ‘Nanotechnology’?
The term ‘nanotechnology’ has two distinct meanings today, and to understand the field and its prospects, it’s important to understand both: They correspond to concepts and research objectives that are quite different, yet mutually supportive.
As illustrated by the set of dictionary definitions noted below, the most widespread concept of nanotechnology is relatively specific: it defines the field as a technology that centers on atoms, molecules, and atomically precise fabrication. The more recent concept, generally accepted within the field that it defines, is much broader: it embraces diverse areas of science and technology that are concerned with “matter at dimensions between approximately 1 and 100 nanometers”.
After looking more closely at these two concepts and the role they‘ve played in the development of nanotechnology, I’ll offer some observations about where we stand today and suggestions about ways forward: Some systematic shortcomings in the exploitation of past developments present researchers today with a rich array of under-exploited opportunities.
A sample of meanings:
Definitions of ‘Nanotechnology’ at Dictionary.com
The online resource Dictionary.com provides the following collection of recent definitions for ‘nanotechnology’. Several define nanotechnology as a technology based on fabrication processes involving atoms and molecules, one defines it as any technology on the scale of nanometers, and one notes both of these definitions.
...as a technology involving atomically precise fabrication:
“The science and technology of building devices, such as electronic circuits, from single atoms and molecules.”
American Heritage Dictionary of the English Language
“The science and technology of devices and materials, such as electronic circuits or drug delivery systems, constructed on extremely small scales, as small as individual atoms and molecules… Our Living Language: Nanotechnology is the science and technology of precisely manipulating the structure of matter at the molecular level. The term nanotechnology embraces many different fields and specialties…”
American Heritage Science Dictionary
“A hypothetical fabrication technology in which objects are designed and built with the individual specification and placement of each separate atom.”
Jargon File 4.2.0
...as either atomically precise OR nanometer-scale fabrication:
“Any fabrication technology in which objects are designed and built by the specification and placement of individual atoms or molecules or where at least one dimension is on a scale of nanometers.”
The Free On-line Dictionary of Computing
...as nanometer-scale technology of any kind:
“Any technology on the scale of nanometers.”
Random House Dictionary
http://dictionary.reference.com/browse/nanotechnology, retrieved 11 August 2009
The story and concepts behind the term “nanotechnology”
Turning for a moment to the historical context, it becomes clear that the majority of the definitions above reflect the concept of nanotechnology as it first emerged, together with the first active use of the term*, in a big public splash in the late 1980s (See “When the first million readers encountered nanotechnology”). Nanotechnology, as it was then described and understood, is a field that promises to deliver large-scale, general purpose, atomically precise fabrication with a host of revolutionary applications. It is this promise that created the widespread perception of nanotechnology as an exciting technology of the highest order.
The diffuse aura of wonder that came to surround nanotechnology (marketers soon hyped nanopants, nanoshampoos, and so on) in the 1990s spilled outward from this excitement, not from a sudden public fascination with potentially useful size-dependent phenomena in nanoscale structures. Causality ran in the other direction, as a excitement about a steadily broadening concept of nanotechnology spurred a fresh focus on nanoscale phenomena, an unprecedented wave of support for research in the area, and with this, the coalescence, definition, and institutionalization of a new field. The result was Federal support for a multi-year, multi-billion-dollar program, the U.S. National Nanotechnology Initiative
At that time, atomically precise fabrication was an essential part of the definition of nanotechnology. For example, a widely distributed promotional document, the “National Nanotechnology Initiative: The Initiative and Its Implementation Plan” (July 2000, 144 pages), was addressed to “MEMBERS OF CONGRESS”, and its second section begins with the following title and statement:
2. Definition of Nanotechnology
The essence of nanotechnology is the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization.
In its list of Grand Challenges, the executive summary includes “Making materials and products from the bottom-up, that is, by building them up from atoms and molecules”. The document includes extensive discussion that uses similar language.The program as actually implemented, however, embraced the now-familiar size-based definition of nanotechnology. The December 2009 version reads:
What is Nanotechnology?
“Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale.”
http://www.nano.gov/html/facts/whatIsNano.html, retrieved 11 August 2009
This carefully crafted language defines a field and funding program of broad scope; it explicitly mentions instrumentation, generic nanoscale fabrication technologies, and nanoscale science in general. Although this scope extends far beyond the concept of nanotechnology as atomically precise fabrication, it is highly compatible in a practical sense: It encompasses both a wide range of technologies that contribute to advances in atomically precise fabrication, and a still wider range of technologies with applications that help drive forward the field as a whole.
The problem with this definition isn’t what it includes, but what it omits: It makes no mention of atoms, molecules, or atomically precise fabrication, said to be “the essence of nanotechnology” when the program was established.
As this omission might suggest, research in atomically precise fabrication has, in fact, been funded chiefly by other agencies and programs. These have regarded it as a branch of the biomolecular sciences, and the NNI (like similar programs elsewhere) have done surprisingly little to integrate this work with the rest of nanotechnology.
This points to both a problem and a corresponding opportunity.
Looking forward: Exploiting progress, fulfilling promise
Although advanced atomically precise fabrication was part of the promise that motivated Congress to initiate and fund a nanotechnology research program (as shown, for example, by congressional testimony at the time), the omission of this objective has been characteristic of NNI documents. This anomaly is a residue of conflicts of perception and politics that surrounded the establishment and initial funding of the NNI itself in FY2000.
The anomaly reflects a set of priorities that resulted in what was, from the perspective of atomically precise fabrication, a poorly balanced and coordinated research program. For example, developments in macromolecular engineering and self-assembly have (by several metrics) provided the most advanced form of atomically precise fabrication, and provides an approach to organizing both organic and inorganic components to form precise, three dimensional structures. Further, this line of research is central to the development of biomimetic, ribosome-class molecular machine systems, a prospective next rung on a ladder of progressively more capable and economical technologies for atomically precise fabrication. Nonetheless, for many years this research was seldom regarded as part of nanotechnology; support has come from other directions, and for other reasons.
As one might expect, this separation of research fields — and concepts — has delayed the integration of molecular, biomolecular, and inorganic nanotechnologies. The minimal support for exploration of pathways toward ambitious objectives in atomically precise fabrication reflects a more general pattern of inadequate support for integrative design and development of atomically precise systems of all kinds, including chemical, mechanical, and electronic.
This problem in the past creates an opportunity in the present: Inadequate exploitation of the riches delivered by past research presents researchers today with a rich array of under-exploited opportunities. A moderate shift of attention toward atomically precise components and atomically precise self-assembly could reap great rewards across a broad spectrum of research areas, and could strengthen the connection of the field as a whole with the promise that launched it, and that continues to sustain much of its public support.
* To the best of my knowledge, the only prior use of an almost-identical coinage (‘nano-technology’) appeared in a 1974 paper by Prof. Norio Taniguchi. The paper, published by the Japan Society of Precision Engineering in the proceedings of a production engineering conference held in Tokyo, discussed prospects for several nano-precision fabrication processes.