what has brought this dream within reach is researchers’ new-found ability to image and manipulate individual atoms. In the early 1980s, physicists at IBM Research in Zurich invented the scanning tunneling microscope (STM), which made it possible for the first time to capture direct images of matter at the atomic scale. This was the discovery that opened up the nanoworld. Relying on the STM and a closely related instrument called an atomic force microscope (AFM), scientists can now directly push atoms and molecules about and prod them into place.
There are two forms of atomic manipulation. One involves physical manipulation to slide atoms around on a metal surface to form 2-D structures. The other approach attempts to fabricate stable structures with atomic resolution by breaking and forming chemical bonds, using the strong electric fields generated by the STM apparatus itself.
These are still exotic laboratory investigations. But for those in corporate and university research labs, the development of these powerful new tools means that “you can go hog-wild in imaging and manipulating entirely new physical structures,” according to Donald Eigler, a physicist at IBM Almaden Research Center in San Jose, Calif. Eigler’s group is, for example, studying the magnetism of several atoms perched on a surface. While the work using STM could eventually lead to advances in computing and magnetic data storage, Eigler is not driven only by practical applications. “What gets me most excited,” he says, “is when I see an aspect of nature that has not been seen before. This is new turf.”
The boundaries of this new turf are still being drawn in a sometimes contentious debate. Most physical scientists report that nanospace is a mysterious place that operates according to its own rules. And even researchers like Smalley who believe the work will eventually pay off in significant benefits for society point out that they are just beginning to understand the physics of the very small and learn how to control behavior in this realm.
A few, however, maintain they have it all but figured out. For nearly two decades, K. Eric Drexler, chairman of the Palo Alto, Calif.-based Foresight Institute, a nonprofit group that aims to promote nanotech, has been describing in precise detail how nanomanufacturing will work-and change the world. Drexler envisions self-replicating nanorobots that mechanically push atoms and molecules together to build a wide array of essential materials. Huge numbers of these nanorobots working together would supply the world’s materials needs at almost no cost, essentially wiping out hunger and ending pollution from conventional factories.
It’s a utopian vision that few researchers doing experiments on the nanoscale have bought into. But, not surprisingly, it holds a vast appeal for many others. This notion of nanotechnology has taken on a life of its own. And for a broad audience of technology enthusiasts, as well as for some in the media, it has become the best-known version of the nanotech dream.
That, according to some scientists, is exactly the problem. Drexler’s ideas may have helped create early excitement for nanotech, but after years of hearing grandiose speculations of a brave new nanoworld, researchers say it’s time to let the science overtake the fantasies. “There has been no experimental verification for any of Drexler’s ideas,” says Mark Reed, a nanoelectronics researcher and head of Yale University’s electrical engineering department. “We’re now starting to do the real measurements and demonstrations at that scale to get a realistic view of what can be fabricated and how things work. It’s time for the real nanotech to stand up.”
Some argue that the advent of practical nanotech is already here. It is a modest start. Scientists are not yet building practical electronic devices out of single atoms or molecules-and there are definitely no nanorobots around. But Richard Siegel, a materials scientist at Rensselaer Polytechnic Institute who headed a National Science Foundation-sponsored report last year on nanotech, says controlled synthesis of materials on a nanometer scale has already begun. The report also concluded that a worldwide race to exploit nanomaterials and build nanodevices is well under way, led by numerous university research groups and large industrial labs such as IBM Research, Motorola and Japan’s NEC Fundamental Research.