A new USC Nano-Imaging Center has opened on the University Park Campus for scientists and engineers probing the mysteries of nanoscale materials and systems.
Dr. Byungmin Ahn, a Center for Nano-Imaging post-doctoral researcher, left, stands next to one of the new scanning electron microscopes. Viterbi School Prof. Steve Nutt, director of the M.C. Gill Foundation Composites Center, is on the right.
The center, which was unveiled Dec. 11 at a special symposium, houses three new scanning electron microscopes (SEMs). These instruments will allow researchers from a broad range of the biological and physical sciences to gain a better understanding of nano-materials using the latest, most sophisticated 3-D imaging technology available.
Creation of the new center, a core lab operated jointly by the Viterbi School and the College, is located in the engineering school’s Center for Electron Microscopy and Microanalysis. The facility represents an important investment to strengthen USC’s research infrastructure and position the university as a national leader in nano-imaging, nano-analysis and nano-fabrication, said Dennis J. Atkinson, director of Corporate Research Advancement.
Chemical engineering and materials science professor Steven R. Nutt, who directs the Viterbi School’s M.C. Gill Foundation Composites Center, believes the new instruments will transform the microscope from a device for static observations to an instrument for bold and vigorous experimentation.
“These new imaging instruments will support multi-disciplinary research in biomedical nanoscience, which could lead to discoveries in the early detection and more effective treatment of disease, as well as the development of prosthetic devices that restore function to tissue and organs," Nutt said. “They will allow us to pursue 3D nano-imaging, nano-machining and nano-manipulation in a big way.”
Researchers from USC, Boston College, JEOL (Japan Electron Optics Laboratory), EDAX, Inc., which makes high performance X-ray instrument components, and The Aerospace Corporation gathered in Davidson Conference Center for a series of talks entitled, “The Changing World of Electron Microscopy,” before taking a tour of the new facility. The new instruments, considered state-of-the-art for nanoscience imaging and fabrication, were procured with funds from the Provost’s strategic Biomedical Nanoscience Initiative, in cooperation with JEOL, and will be available to all USC faculty and students.
“JEOL recognizes USC as one of the elite research universities and values its leadership role in pioneering new frontiers in nanoscience,” said Pete Genovese, vice president of JEOL, USA.
The JSM-7001F, a field emission gun scanning electron microscope.
The new SEMs, which have different capabilities, utilize an electron beam to scan the surface of a sample, be it biological or inorganic, Nutt explained. The beam generates a signal that is detected and mapped to a viewing screen, where an image is created and can be magnified up to several hundred thousand times. Researchers can achieve high resolution on the order of a few namometers.
“One of the most exciting capabilities we will have is something called a FIB, or focused ion beam,” he said. “Essentially, the SEM is combined with a second machine, the FIB, and both beams are focused on the sample. The electron beam will image the sample, but the FIB can be used to cut or machine the sample while imaging it with the electron beam. This enables the user to machine the sample while watching the process at high magnification.”
Three basic tasks can be performed with FIB capabilities, Nutt said. The first is progressive sectioning, using the ion beam to cut sequential slices of the sample, like slicing ultra-thin lunch meat. The user can slice, image, slice, image, and so on and so on, progressively revealing the internal structure of the sample. Saving the sequence of images also lets the researcher reconstruct a 3D image of the internal structure, a process called “3D reconstruction,” which is a powerful visualization tool.
Researchers can also perform site-specific TEM (transmission electron microscope) sample preparation. This process utilizes a second type of electron microscope, the TEM, and requires preparation of ultra-thin sections of a sample that are electron transparent, Nutt said.
“The TEM sample prep is tedious and skill-intensive when performed by grinding and polishing, but the FIB can be used to prepare the thin sections in the SEM,” he said. “This is particularly valuable because the researcher will now be able to prepare a thin section from a specific region of interest, something that was extremely difficult to do by conventional means.”
The third task is machining and deposition. A researcher can sculpt and machine nano-scale and micro-scale devices and structures, perform ion-beam lithography, and build super small configurations that were previously very difficult or impossible to build.
Jaap Brink, JEOL, TEM applications specialist and conference speaker.
"We expect these machines will be widely used in the physical sciences, life sciences and the engineering community,” Nutt said. “For example, they can be used to analyze nanostructures for electronic and photovoltaic devices, as well as for structural applications.”
As the design and fabrication of devices shrinks to the nanoscale, scientists desperately need the ability to see what they have created, Nutt emphasized. However, he views these machines as much more than just microscopes; he sees them as platforms for dynamic experiments, in which researchers can observe changes as they occur. The researchers will also be able to modify and build structures in situ, like carbon nanotubes or modified viruses to deliver antibodies to specific cells, while simultaneously observing the structures at high resolution.
“This opens the door to a new kind of science in which we will be able to observe nano-scale phenomena with unprecedented detail," Nutt said.
