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A dust-free facility to handle the campus nanoscale boom
By mid-November 2007, before much of the equipment had even arrived, science faculty members on the Middle Campus were regularly making the 1.5 mile trek from their labs to a new, and long-awaited, “clean room,” which occupies much of the second floor of the Kenny-Cottle Library on the Newton Campus. “Everyone in my lab is over there several times a week,” Physics Department Chair Michael Naughton said at the time.
This lively interest in a 1,500-square-foot space housing an array of specialized scientific tools in a virtually dust-free atmosphere betokens the rise of a field called nanotechnology, which involves the construction of tiny electronic and mechanical devices sized between one and 100 nanometers. (One nanometer, a billionth of a meter, is the size of 10 atoms laid end to end, or one eighty-thousandth the diameter of a human hair.) Nanoscale devices have to be made in an ultra-clean setting because contamination with a single dust speck can render them useless, according to Naughton.
Given this constraint, what’s the benefit of working on the nanoscale? “When you get down to that size, you’re getting down to the scale on which [biological] events occur,” says Thomas Chiles, biology department chair, “and so it’s much easier to study [biology]” at that scale. Moreover, says Chiles, many nanostructures are bio-compatible—they are non-toxic to living cells—and may be just right for medical uses, such as drug delivery. One frequent clean room visitor, Dong Cai, a research associate professor of biology, is working with Chiles on a biosensor that uses nanostructures to detect pathogens and chemical contaminants. Potential applications include medical testing, food safety, military surveillance, and quality control in the pharmaceutical industry.
Another lure of working on the nanoscale involves the novel properties of nanoscale objects. For instance, because light has a nanoscale wavelength, nano-scale devices are ideal for collecting and manipulating light. Naughton, who led the four-year effort to fund and build the clean room, at a cost of $7.6 million, uses the new facility to experiment with tiny light-absorbing antennas that he hopes will form the basis for a treatment for blindness. He traces the beginnings of nanotechnology to the computer chip industry, which developed the tools for building tiny circuitry in the middle 1980s. After years of incubation, he says, the field is now “exploding.”
The field has in fact been expanding at Boston College, with scientists in physics, biology, and chemistry working alone and collaboratively on nanoscale projects. Before the clean room opened, Boston College scientists were forced to rent time at the MIT, Harvard, and Cornell clean rooms, where off-campus users have to make reservations, sometimes months in advance. Borrowing another institution’s clean room “has severe limitations,” Naughton says. “You go there, make a bunch of things, put them in a car or plane, and have them possibly degraded or ruined on the trip home. Then you set up a bunch of tests in your lab and discover ‘that parameter should have been 7 instead of 8. Let’s schedule more time four months from now.'” Naughton adds that in recent years the University’s lack of a clean room made it harder to recruit science faculty.
Dunwei Wang, an assistant professor of chemistry who started at BC this year, is working on a solar-powered nanoscale device that breaks hydrogen atoms off from water and harvests them for use in fuel cells. “Without the clean room,” Wang says bluntly, “I wouldn’t be here.”
Clean rooms are rated by their air purity. Boston College’s clean room is class 10,000, which means that a cubic foot of air in the room holds no more than 10,000 dust particles. While that sounds pretty dusty, “it’s probably 100 times cleaner than outdoor air,” says Naughton.
The device that keeps the clean room clean, known as an air handler, takes up a separate room down the hall. A steel box about eight feet tall and 25 feet wide, it uses pumps and filters to change clean room air about once a minute, says the facility’s director, Stephen Shepard. Another nearby room holds equipment that cools and dehumidifies the clean room air and pipes in a glycol-and-water mixture to cool those devices that operate at high temperatures. In the “service chase,” the corridor outside the clean room, are parked maculate items such as oily pumps and dusty steel bottles of compressed gas, which are connected by hoses and pipes to equipment in the clean room proper.
Before entering the clean room, scientists don hairnets, booties, and white coveralls known as bunny suits in a gowning area. The clean room itself is blinding white, with white-painted walls and white floor and ceiling tiles, along with windows that look out on the service chase. Nanofabrication and test equipment lines the walls. A random sampling includes ultraviolet photolithography equipment that uses printing technology to build tiny circuitry and machines; a probe station, which measures the electrical properties of nanoscale circuits; and an atomic force microscope with a resolution of less than one nanometer.
The clean room also holds such specialty items as a sputtering evaporator, which knocks particles off a metal “target” and sets them down in a layer several nanometers thick on a substrate, a flat piece of glass or plastic; an atomic layer depositor, which can set down materials on a substrate in a layer that’s a single atom thick; and a focused ion beam device that can cut and carve materials with under one nanometer of precision. Everything in the room is state of the art, according to Shepard, who formerly worked for the MIT clean room and was clean room manager at Harvard.
To Dunwei Wang, who has recent experience working in clean rooms at two other august institutions—Stanford University, where he earned his doctorate in 2005, and Cal Tech, where he did a post-doctoral year—the Boston College clean room “is equal and, in some tools, superior” to those facilities. “We have whatever equipment we need,” he says, “and of what we need, we have the best.”
David Reich is a writer based in the Boston area.
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