Still "Plenty of Room at the Bottom": Nanoscience at Caltech Twenty Years On

The Kavli Nanoscience Institute at Caltech, a 21st century center for science and engineering at the nanoscale, celebrated its 20th anniversary with a special symposium and a fireside chat between President Thomas F. Rosenbaum and 2022 Kavli Prize Laureate George M. Whitesides (PhD '64) from Harvard University on March 7–8, 2024.

Throughout history, people have marveled at large things. Blue-ribbon-winning giant pumpkins, 7-foot humans, the Great Pyramid of Giza, and the cosmos itself have all captured humanity's imagination. But from the invention of the optical microscope in the 16th century to the silicon-based microchip in the mid-20th century, scientists and engineers have become equally intrigued by very very small things. Now, with the advent of sophisticated microscopy instruments, tiny objects as small as several nanometers in size can be measured by researchers such as those at Caltech's Kavli Nanoscience Institute (KNI), which celebrated its 20th anniversary with a special symposium and a fireside chat between Caltech President Thomas F. Rosenbaum and 2022 Kavli Prize Laureate George M. Whitesides (PhD '64) from Harvard University on March 7–8th, 2024.

Just how small is a nanometer? If you're thinking "small," think smaller. Nano, Greek for dwarf, is one billionth of a meter: 0.000000001 (10-9 meters). A single sheet of ordinary paper is 10,000 times as thick as a nanometer, as is the diameter of a single strand of human hair. One nanometer is the length of about 10 atoms depending on the atom. Or to keep it close to home, consider this: Your fingernail grows by about 1 nanometer every second.

Despite their vanishingly small size, nanoscale materials can be incredibly strong—more impact-resistant than Kevlar, for example—and can perform amazing feats that we are only beginning to harness, such as the ability to refract light backward.

Nanotechnology—currently defined as the design, fabrication, or use of structures between 1 and 100 nanometers—is said to have begun in 1981, with the development of the scanning tunneling microscope (STM), which is capable of scanning over and imaging individual atoms. It was predicted decades earlier by the late Caltech professor Richard Feynman in a 1959 speech to the American Physical Society, "Plenty of Room at the Bottom," where he spoke of miniaturizing computers and storing the 120,000 volumes in the Caltech library "on just one library card."

Although Caltech scientists began experimenting with nanotechnologies as soon as they were available, it was not until the formation of the KNI and the construction of the KNI Cleanroom in 2003 that a single place existed on campus that housed instrumentation capable of virtually all aspects of nanofabrication: photo-, ion- and electron beam lithography, deposition, wet and dry etching, electron microscopy, and more. In turn, this facilitated collaborations among researchers on campus focused on nanoscale phenomena. Fred Kavli of the Kavli Foundation was instrumental in brainstorming the future of nanoscience with the Caltech faculty and administration, and providing initial funding along with the Gordon and Betty Moore Foundation. Later funding has come from the Fletcher Jones Foundation, Chuck and Judy Wheatley, and the Space Solar Power Project.

KNI has given Caltech scientists on campus and at JPL, as well as researchers from other universities and companies, the ability to work at the nanoscale. Today, about 10 percent of Caltech's faculty or members of their research groups use KNI's instruments. The facility draws researchers from across scientific disciplines, including applied physics, materials science, biology, chemistry, engineering, and astronomy. "Once users are fully trained and signed off to use the equipment, they have 24/7 access to the facility," explains Tiffany Kimoto, KNI's executive director. "We also have had several corporate users over the years who have used our facilities, including Samsung, Meta, Nokia, and several start-ups, especially those founded by Caltech personnel."

"It is exhilarating to think about everything that is possible at the nanoscale, and how many more challenges remain," says Julia R. Greer, the Fletcher Jones Foundation Director of the KNI and Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering. "We are getting really close to fabricating, manipulating, and imaging samples at the atomic level, which propels new discoveries just about every day."

Projects undertaken at KNI include prototyping new materials that can resist impact or store energy, growing and characterizing quantum materials and two-dimensional van der Waals materials for topological quantum devices and nanophotonics, identifying rare proteins, and building nanodevices that connect single photons to individual atoms and nanodevices that can store and release photons on demand. These are just some of the ways Caltech researchers have been working on science's cutting edge with KNI's help. To learn more about these efforts over the past 20 years of KNI's existence, click through this slideshow.