After having taken a look at some snippets of nanotechnology, can we venture a useful definition? Alas, it is difficult. The field is still so new that most do not agree on a definition. Moreover, since there is a flood of funding for the field, many are claiming they are doing nanotechnology, when perhaps they are not (the definition then seems to be "anything small enough to be really expensive"). The situation is not clear-cut. Is producing nanoparticles to be considered nanotechnology? If so, then the colloid chemists beat the rest of the world to it by many years. Synthetic chemists, also, have been producing structures nanometers in size with exquisite control for quite some time now. Was that nanotechnology? What is nano?

      I will present a few definitions from various sources, and then try to give my own definition. Undoubtedly, many will argue with my definition, as I am arguing with theirs, but this is all part of the process of a discipline maturing.

      The Oxford English Dictionary defines Nanotechnology as: "The branch of technology that deals with dimensions and tolerances of 0.1 to 100 nanometres, or (gen.) with the manipulation of individual atoms and molecules. "(1) This is the definition we started with, and, unfortunately, is not exact enough to define the field. After all, what does it mean to manipulate atoms and molecules? When a synthetic chemist assembles a complex organic molecule, did he "manipulate" the atoms that went into it?

      Those in industry actually seem to agree with the above definition. They are much less concerned with the philosophical ramifications of the question, and consider nanotechnology to be "just small microtechnology." Essentially, then consider anything in the size-scale of microns to 100s of nanometres to be "microtechnology" and anything in the size-scale of 100s of nm to about 1nm to be nanotechnology. To me, this turns nanotechnology into a rather boring discipline. The excitement in the field stems from the fact that we hope to do things in a different way. We do not merely wish to prove that we can make smaller and smaller microchips, but to in fact show that we can build things in ways that was previously unheard of. We want to make not just better technologies, but new technologies.

      At the first conference for the newly formed NanoQuébec funding agency, the organizers were careful to encourage participants to accept that nanotechnology would have to be more than merely nano versions of tried and true microtechnology. They offered the following definition (presumably the one they will use to evaluate funding requests):
            For a system to be considered 'Nanotechnology' it must:
            1. Have a critical length scale, Lc, in at least one spatial dimension, on the order of nanometres.
            2. The behavior of the device must be qualitatively different below the scale Lc.
      This definition, of course, includes the "nanometre," but also requires that the properties under investigation be different than those at larger length-scales. Thus, making a 30nm transistor is not, in their opinion, nanotechnology, since it operates in exactly the same way as do 1000nm-sized transistors (being much faster is only quantitatively different, not qualitatively). If the transistor is made small enough that it begins, for example, exhibiting quantized charge transport, then we have entered a new regime, and the device should indeed be called nanotechnology.
      While I agree in many ways with the intent of this definition, it also troubles me. Alas, most of the examples which can be suggested for scaling behavior which sharply becomes qualitatively different at the nano-scale are quantum mechanical in origin. In my opinion, nanotechnology is not simply the Siamese twin of quantum technology. In fact, if a device operates based on quantum principles (such as proposed quantum computers), I think it should be classified as just that: quantum technology. Do the other aspects of nanotechnology really fulfill the above definition? Self-assembly works at the micron and even the millimeter size scale quite well. Does that invalidate nano-scale self-assembly from the realm of nanotechnology? (Granted self-assembly works much better, and can do much more at the nano-scale, but isn't that just a quantitative difference?) The carbon nanotube transistors mentioned before work quite like conventional transistors? Does that make them non-nano?

      The difficulty in deriving a satisfying definition should now be evident. What I find also interesting is that most definitions also miss something obvious: "technology." I don't think we should consider it nanotechnology until it does something useful for humankind. Anything before that is just "research towards nanotechnology," or, more likely "studies in nanoscience." Thus I offer the following definition, which necessarily is in two parts:
            Nanoscience is the study of the behavior of systems on the scale of the nanometre (0.1 to 100nm), with the specific goal of understanding the qualitative and quantitative differences of that size scale (in, for instance, scaling laws, dominant forces, and behavioral peculiarities).
            Nanotechnology is the application of knowledge from Nanoscience, with the goal of exhibiting control of matter with nanometre resolution, in order to generate useful technological devices, with effects translated to the macroscopic regime.
      I propose this cumbersome definition for many reasons. First, it separates the science from the technology. If you are studying nanoscience, it is to understand what is different about the nano, not just to make pretty shapes that happen to be nanometres in size. If you are making nanotechnology, then it must have some (eventual) benefit to humankind. On the other hand, for it to be nanotechnology, it must be something that could not have been done at other size scales (for quantitative or qualitative reasons), and it must have required special knowledge of the nano regime. I also require that the nanometre-sized control be extended in some way to the macroscopic regime. This may be due to addressibility on some substrate (via lithography, for instance), or by inclusion in some sort of hierarchical material (which has periodic structure at multiple length scales), or perhaps only by macroscopic manifestations of behavior (such as the healing of a sick patient). In essence, I do not feel that isolated nanometre-sized objects really constitute nanotechnology. Not until some (macroscopic) person can interface with them in some way.

      Again I remind the reader that the above definition is merely my own, and is subject to change without notice. Hopefully as the field grows, there will be wild new ideas which will emerge. Most will fail, and will not be included in the final form of the definition, whereas some will become the defining features of the field. For now, we need to continue trying different things. Eventually, the definition will be as clear-cut as that of "biology," "chemistry," "physics", or "math" (which are, of course, blurry in their own way).

      To conclude, here is the Cole's Notes version of my talk:

•       Lithography will continue to advance (sneaking into the nano-regime), but this cannot continue forever. In addition to ever more clever lithography, we need entirely new manufacturing paradigms.
•       Understanding of the behavior of molecules, and behavior in general at the nano-scale, will lead to smaller (presumably better) devices (ex: nanotubes).
•       Self-assembly may permit nano-devices to be built with startling ease, but we are still a long way from understanding self-assembly. We need to have greater insight into the process before completely rational designing can begin.
•       "Borrowing" from nature will likely be a fruitful paradigm for advanced nanotechnology.
•       We are still a long way from agreeing on what it is. This is evidence of the nascent nature of the field. This is what makes it exciting: there are no rules yet.

      And finally: Thank you for your kind attention!

1.Reproduced from: http://dictionary.oed.com/

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