Running Out of Time

Mike Treder writes "CRN Director of Research Chris Phoenix is currently attending a week-long IEEE Conference on Nanoscale Devices & System Integration in Miami, Florida. Chris will present a paper titled "Studying Molecular Manufacturing" at the conference later this week, and he'll be updating us with his impressions every day or two. Here is his first report:"

Chris Phoenix reports from the IEEE Conference on Nanoscale Devices & System Integration in Miami, Florida:

It's amazing how far things have come in a year or two. Much farther than I had expected. I'm actually out of date! The last I knew, dip-pen nanolithography was a cutting-edge proposal, and drug design was an arcane art. One person literally laughed at me for the latter opinion. And a MEMS researcher mentioned DPN, a bit dismissively, as a "standard" (or was it "conventional"?) lithography technology.

If you go to a foundry, see a statue you like in brass, and ask them if they can cast it in iron, they'll probably say, "Sure." They've been working with metals for decades, so the form is almost independent of the process. Well, the same thing is happening-strike that, it already has happened-with even the most recent nano-lithography processes. I asked someone if he could take his cutting-edge silicon MEMS work and redesign it in two-photon stereolithographic polymer, and he said, "Sure."

I then asked him if he could design me a four degree of freedom SPM system. He had to think about that one, and in the end he wasn't sure. But just a year or two ago, it would have been unthinkable.

So, when the "Nanhattan Project" finally gets started, it will have absolutely no problem finding not only dozens of nanoscale techniques, but people willing and able to combine them. These are not world-class researchers-they're grad students and postdocs. Well, maybe these days the grad students are the world-class researchers. No wonder the dinosaurs are scared.

The coolest thing I saw today, though, was a set of technologies-all from the same lab-for using light on semiconductor chips. Remember the sub-wavelength techniques I wrote about in the last C-R-Newsletter? ( Add these to the list, at the top.

It used to be thought that light had to travel in a space large enough for its wavelength. Nope! Make a very narrow trench-50 nanometers, maybe 1/10 or 1/20 of a wavelength-and the light will be quite happy traveling along the overlapping electron clouds from the sides of the trench (or something like that). Unlike optical fibers, the light travels through the region with the lower index of refraction.

To link a 0.05-nm trench to a 10-micron fiber, do you just butt them together? No, that transfers at most 3% of the light. Do you use a gradually widening cone? You can, but it'll take a very long distance. The right answer is to narrow the thing still further, making a needle only 20 nm long-and the light escapes out the sides, and up to 95% of it goes into the fiber; they've already demonstrated 70% transfer, and it's relatively insensitive to misalignment.

As far as I know, this doesn't have much to do with molecular manufacturing, or even with enabling technologies for it. I describe it because first, it's incredibly cool; and second, it's evidence that the previous stuff-nanolithography, chemistry, manipulation-is already a mature field, no longer so cutting-edge. Still lots to learn, but it's ready for application.

In the poster session, one group reported a fuel cell they'd made with microporous silicon, gold-plated on one side, sandwiching a membrane common enough to have a trade name. It's a square centimeter and 800 microns thick, produces a quarter watt, and runs on methanol at room temperature with high efficiency. I asked if this was commercially competitive: "Oh, Yeah!" Is this a highly funded fuel cell research team? No, it's a few students in a lab, working on something else entirely. They just did the fuel cell thing "for fun." Next I wandered over to the bookstore table, noticed a book on fuel cells, opened it at random… "All low and medium temperature fuel cells require pure hydrogen." The book was published two years ago.

Tomorrow morning I'm going to hear talks on:

  • Atom beam lithography: proximity printing for the sub-10-nm domain.
  • Nanorobotic manipulation and manufacturing systems.
  • Design principles for self-assembling devices from macromolecules.

Could we have diamondoid molecular manufacturing in five years? There's no doubt in my mind that we could. If we really tried, we might have it in three. Of course, that doesn't mean we will-but the important technologies are mature enough to be portable, so if we don't, someone else will… soon.

We're rapidly running out of time to prepare.

Chris Phoenix

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