Horst Störmer kicks back in his spacious office in Columbia University's new Nanoscience and Engineering Center. Out the window are sweeping views of uptown Manhattan and the campus where the Nobel laureate in physics is learning a new craft: chemistry. "Biology never invented the copper wire," he proclaims. "Electric signal transmission in your body and brain is terribly slow -- really just a bucket brigade [of cells] passing ions along," he says. In contrast, electricity flows through the copper wire on computer chips at close to the speed of light. Yet, he adds, biology pulls off one thing that trumps humanity's best technology: Starting with just two cells, it builds people with complex brains that sparkle with creativity. Biology's chemical factory, he marvels, regularly pulls off wonders of self-assembly.
Combine those same powers of self-assembly with modern materials, and it could mean the Next Big Thing in the world of computing. That's the goal driving much of his work at Columbia's Nanocenter.
Under the guidance of Störmer, who is one of three directors, scientists are working to harness molecules' natural ability to bond and assemble -- and organize into high-performance, nano-size transistors and sophisticated circuits that will make today's computer chips seem like simpletons. Finding the key to nature's self-assembly bag of tricks also promises to help end the need for billion-dollar chipmaking plants and shrink electronic chips down to the molecular level. That promise is why Störmer, at age 56, is venturing into the world where physics meets chemistry.
While a young scientist at Bell Laboratories in the late 1970s, Störmer pondered the mysteries of quantum mechanics -- a realm of physics where subatomic particles defy classical rules and everyday logic. In 1981 he and fellow Bell Labs researcher Daniel Tsui were examining how electrons move through semiconductors under powerful magnetic fields and at extremely low temperatures. They made a bizarre discovery: Electrons can lose their discrete charge and behave as a sort of fluid. The observation, which was explained in theory a year later by Robert Laughlin at Lawrence Livermore National Laboratory, led to new understanding of the properties of subatomic particles. In 1998, the three scientists shared a Nobel prize in physics.
These days, Störmer is hoping to make a similar leap of discovery in the emerging field of nanoelectronics. If Moore's Law, which calls for computer power to double every 18 months or so, is to hold, just making transistors smaller will no longer be sufficient. For tomorrow's nano-size devices, the challenge is connecting them into functioning circuits. To illustrate the problem, Störmer holds up a pencil. If it were a molecular-sized transistor, attaching today's skinniest wires, he says, would be like tacking a truck on either end. So it's vital for connecting wires to self-assemble. But mimicking biology's secrets enters a "no-man's land" between chemistry and physics. In Störmer's group, chemists and physicists work side by side to understand how electricity travels through organic molecules, and then tease them to assemble into complex structures.
The center's work is in its early days. The team is still exploring various molecules to determine which are duds as semiconductors and which could be high-performance wonders, and why. "You've got the whole periodic table and all its possible combinations" for building candidate molecules, says Störmer. "At some point, somebody's going to come up with the molecule" that will replace silicon. Then the circuits for future computers and electronic gear will fall into place naturally, assembling themselves.
By Burt Helm