Big Idea for Nano Research
Photo: Prof. Horst Stormer and Ph.D. student Jun Zhu perform low temperature measurements on nanostructures.
In the late 1970’s, when Mork from Ork said “Nano, Nano,” no one could have predicted the importance of that phrase three decades later. Nano- is the prefix for one of the fastest growing areas of science and technology—research at the itty bitty, really, really tiny scale of a nanometer: one billionth of a meter. Nanoscale science is conducted on dimensional scales ranging from individual atoms to large molecules. The capability to miniaturize beyond the micro-scale into the nano-scale will impact fields as diverse as electronics, medicine, materials, manufacturing, environmental, and information technologies.
Research in nanotechnology may yield a way to implement many science fiction concepts, such as nanoprobes that can be used to diagnose disease or nanoscale devices that can dispense medication at precise locations within the human body. With nanoscale electronic memory devices, for example, storing the entire contents of the Library of Congress could take up the space of a single sugar cube.
This fall, Columbia became one of six universities nationwide to share more than $65 million in National Science Foundation funds to create a center for nanoscale research. “The role of our new nanotechnology center is fundamental understanding,” said James T. Yardley, professor of chemical engineering and managing director of the new Columbia Center for Electronic Transport in Molecular Nanostructures. “We will bring chemistry and physics together, use engineering to span the pure sciences, and build on our collaborative ties with such industry researchers as IBM and Lucent,” he said. For Columbia, the nanocenter means $12 million over five years to investigate electron transport in molecules. Nobel laureate Horst Stormer, professor of physics and of applied physics, and National Medal of Science winner Ronald Breslow, professor of chemistry, are the scientific directors, working with a group of 16 Columbia researchers in the scientific quest toward a single molecule transistor.
The transistor is a key component of electronic systems; it processes data within a computer chip. Transistors on a molecular scale can potentially increase computational capabilities by many orders of magnitude over the conventional silicon-based electronics of today.
“Our research is driven by the expectation that miniaturization of semiconductors will come to an end somewhere between 2010 and 2015, when this technology is expected to reach its physical limits,” said Stormer. “Semiconductors are being made now from the top down, like carving the statue of David out of marble. We will be working to build them from the bottom up, like taking clay and molding a statue. The ultimate workable smallness is one molecule.”
“Chemists and physicists are meeting at the nanoscale,” said Stormer, “and we need to find ways to explore the hybrid area between chemistry and physics. This will involve many disciplines—materials science, electrical engineering, organic chemistry, condensed matter physics—all combined to see how far we can go. It is exciting fundamental research with great potential for technological impact.”
What kind of molecule is needed? “We are looking for one with three connectors, similar to the three legs of a transistor: one to be the on-off switch and the other two legs to conduct electricity between two other surfaces,” said Stormer. “We don’t know what will work, but organic chemists can make designer molecules with all sorts of properties. It could be anything. There will be so many surprises out there.”
“The success of this research at Columbia will come about not only because of the money and the equipment,” Stormer said. “It will be because of the exceptional quality of the people involved. We don’t have a long history of expertise in nanotechnology, but we have a great level of expertise in the underlying sciences.”
Yardley sees his role in the new center as both a synthesizer and a catalyst for the researchers. “My job is to use the experimental concepts from both chemistry and physics, issue challenges to both sides, get the results and then take it the next iteration down. Engineering science will make the bridge between fundamental chemistry and physics. It won’t be easy — it is a big challenge. What we are doing is research in an entirely new area. We are building on scientific expertise and not on things that are already done.” He notes that one of the strengths of the Columbia proposal is the unique existing collaboration with IBM and Lucent researchers that forms a key component of the center. There has been recent activity in the field, notably by IBM, which built several transistors out of carbon nanotubes. Nanotubes, tiny cylinders of carbon that measure about 10 atoms across, are much smaller than today’s silicon-based transistors. The hope in the scientific world is that research in the nano field will allow Moore’s Law (that the number of transistors that can be packed on a chip doubles every 18 months) to continue well beyond 2015 when conventional electronics reaches its limits.
Columbia will be first concerned with the fundamental aspects of electronic transport that will tie into research being done in crystalline organic conductors and carbon nanotube materials. The team will then work to fabricate a single molecule “bridge” connecting two wires to learn the basic principles needed to develop the molecular transistor.
The Nanocenter Team
Professor David M. Adams Physical, Inorganic & Materials Chemistry
Professor Ronald Breslow Biological & Organic Chemistry
Professor Louis Brus Materials & Physical Chemistry
Professor George Flynn Physical Chemistry
Professor Richard Friesner Theoretical Chemistry
Professor Tony Heinz Electrical Engineering & Physics
Professor Irving Herman Applied Physics
Professor Thomas J. Katz Organic Chemistry
Professor Philip Kim Physics
Professor Ann E. McDermott Biophysical Chemistry
Professor Colin P. Nuckolls Materials Chemistry
Professor Stephen P. O'Brien Materials Science & Engineering
Professor Aron Pinczuk Physics & Applied Physics
Professor Horst L. Stormer Physics & Applied Physics
Professor Yasutomo J. Uemura Physics
Professor James T. Yardley
This story was originally published in the Fall 2001 edition of Columbia Engineering News.