LOUISIANA RESEARCH


	When smaller is better How nanotechnology is building smaller, faster electronic devices By Darv Johnson Weilie Zhou, a researcher at the University of New Orleans Advanced Materials Research Institute, knows an eye-catching scientific parlor trick. He can draw a map of Louisiana small enough to fit on the head of a pin-with room left over for 10 million more maps of Louisiana just like it. It's an intriguing bit of sleight of hand, but nanolithography, the technology that Zhou used to draw his map, has serious implications in the world of science, where smaller is almost always better. Smaller means faster computer processors; smaller means more space to store memory; and smaller, at times, can also mean uncovering new and useful properties of a material. Driven by that philosophy, Zhou and his colleagues at AMRI-a consortium of chemists and physicists, and electrical and mechanical engineers established by UNO eight years ago-seek to manipulate and control particles on the smallest scale possible. Their goal is to enhance properties of synthetic materials so that they can perform specific tasks. In doing so, they hope to create materials that are tougher, cheaper and higher in performance than their unaltered cousins. Some at the institute like to say that they are changing the physical universe, one particle at a time. And nanolithography-the ability to write at the atomic level-is their means to that end. The science of shrinking has come a long way in a hurry. Twenty years ago, Zhou says, scientists and engineers were working on the micron scale. For a point of reference, consider that a human hair is some 30 to 120 microns wide. Today, they are down to the nanometer scale-a billionth of a meter-the scale of atoms and molecules. To grasp that idea, it might help to know that an average man is about 1.8 million nanometers tall. Or, if you're still scratching your head, pluck out a hair and imagine splitting it into 50,000 strands. Each one would be a nanometer wide. The pursuit of the small has paid big dividends in fields such as computer engineering. Shrink the size of a computer chip, for example, and all its elements are closer together. Closer together equals less travel time, equals faster-and helps explain why desktop computers are many times speedier than they were a decade ago. Computer engineers who want to go even smaller and faster-and they always do-are at the point where they need a new technology. That's where nanolithography comes in. AMRI's primary tool in the pursuit of nanolithography is its Field Emission Scanning Electron Microscope, a $500,000 investment that AMRI founder and director Charles J. O'Connor calls "one of the best instruments in the country." The device's electron beam can lithograph or burn a shape into a given material. To demonstrate its capabilities, Zhou used the microscope to burn his miniature map of Louisiana. But it can also be used to burn a nanometer-scale printed circuit, with wires just a few atoms wide. Shrinking circuits brings with it a new set of complications for AMRI scientists to surmount. When running a current through a wire just a few atoms wide, O'Connor says, researchers have to consider factors that wouldn't come up if they were working on a larger scale, like the wavelength of the electrons in the wire or how to keep the current from leaking over to another wire and shorting the device. The ordinary rules of circuit-building no longer apply. "This is where classical physics gives way to quantum mechanics," O'Connor says. "The purpose is to see how these circuits work on a nanometer scale. It won't be the same, but a new property of the material might develop." O'Connor describes the changes magnetic particles undergo as they shrink. To a point, making them smaller strengthens their magnetic moment-a boon to engineers who use them for data storage. But shrink them too much and they lose their ability to hold a magnetic moment at all; they become useless for data storage. The properties that nanolithography might reveal in the electronics arena aren't yet clear, but the potential uses of the research are. Recognizing its potential for building smaller, faster electronic devices, IBM has signed on to partner with AMRI on the nanolithography initiative. The project has also caught the eye of the military's R & D arm, the Defense Advanced Research Projects Agency (DARPA), which is considering a $1.5 million grant. "This is cutting-edge research," O'Connor says. "We are starting to explore the limits of operation of electronic devices." Nanolithography is also spilling over into other AMRI initiatives, including medical technology. Backed by a $6 million DARPA grant, AMRI is in the first year of a collaborative venture with Louisiana State University's Center for Advanced Microstructures and Devices (CAMD) and LSU Health Sciences Center in New Orleans on a project known as biomagnetics interfacing concepts, or BioMagIC. The goal is to develop a handheld apparatus-recall Dr. McCoy's device on Star Trek-that uses microfluidics to detect a variety of pathogens, from simple bacteria to anthrax and even chemical warfare agents. Nanolithography is one of the technologies, O'Connor says, that will allow them to create such a sophisticated device in such a small package. AMRI's focus on the small also extends beyond nanolithography. O'Connor says his team is eyeing work on nanophase composites that would mix tiny particles with host solids to make materials with superior strength. That technology could also lead to the creation of "smart" materials that could respond in a specific way to stimuli: they might be used to dampen vibrations, for example, or to absorb radiation and then react to it by changing color. O'Connor notes that several billion dollars has already been set aside by the government through the National Nanotechnology Institute to fund nanophase research for the next few years. "Nanoscale materials," he says, "are just full of promise."