U.Va. Engineering School Professor Jerrold Floro Manipulates Atoms for Increased Functionality

Smaller, but with Big Purpose

January 18, 2008 — In 1965, Intel co-founder Gordon Moore observed that the capacity of integrated circuits was increasing exponentially, doubling the number of transistors a circuit could accommodate every two years. Known as Moore's Law, this trend has continued for more than 40 years, with current capacity doubling about every 18 months.

Logic suggests that Moore's Law can't go on forever. Jerrold Floro, an associate professor in the Department of Materials Science and Engineering at the University of Virginia's Engineering School, projects that, at the current rate of development, semiconductor technology will shrink to the dimensions of individual atoms within 20 years or so.

"Every time you make something smaller, you have many engineering hurdles to overcome," Floro explained. "Devices don't necessarily like being made smaller, because their materials don't function the same way. Devices that are coming out now are on the scale of hundreds of atoms. If we keep shrinking things down, we'll be to a point where we're talking about just a few atoms, and the physics are just not going to work the right way anymore."

While folks at IBM and Intel may be apprehensive over the inevitable limitations of their industry, Floro is excited. As an expert in the science of nanostructures, he joined the faculty of U.Va.'s Engineering School in 2006 after serving for 14 years as a researcher at Sandia National Laboratory in New Mexico. He is now part of a team that is searching for the next technological revolution.

"I'm interested in semiconductors and nanostructures," Floro says. "U.Va. has assembled a significant group of people over the past five or six years who have really enriched the research environment. So it was exciting to come here and have colleagues who are all interested in the kinds of things I'm interested in, but who have different skill sets. It makes for a great teamwork environment."

Floro's focus is building capability for molecular beam epitaxy. His work involves growing single crystal films of germanium on silicon substrates under extremely controlled conditions to create new semiconducting nanostructures.

For a number of years, his work has involved making quantum dots and building an understanding about how and why they form. Through collaborations with former U.Va. engineering professor Robert Hull, Floro hopes to make use of this new material by controlling the size, shape and composition of the germanium dots and where they grow on the substrate.

"We try to control literally every atom coming down to build up the new film," Floro said. "In an ideal world, we put down every single atom exactly where we want it in order to get useful functionality."

While Floro synthesizes macroscopic arrays of nanostructures, he also collaborates with associate professor Petra Reinke, whose work views nanostructures from a truly microscopic perspective with scanning tunneling microscopy, a technique that allows researchers to view individual atoms. Their combined efforts support professor Stuart Wolf's pioneering work in spintronics, which the team hopes will solve the long-term problem of semiconductor evolution.

"It's not just finding tricks to make things smaller," Floro says. "It's finding entirely new ways to do computer logic that aren't being used at all today. These will almost certainly involve materials nanostructures."

— By Linda Kobert