Yale’s new microscope brings atoms’ identities into focus

Yale's newest transmission electron microscope can provide clear images of objects as small as 0.2 nanometers -- less than 1/100,000th the width of a human hair -- and identify the specific atoms and molecules in samples. (Photo by Michael Marsland)

Yale’s acquisition of a powerful new transmission electron microscope (TEM) is expected to transform researchers’ ability to examine and manipulate atom-scale materials and devices on campus.

The approximately $2 million, state-of-the-art microscope offers atomic resolution for both physical structure and chemical composition, as well as significantly faster processing times than other devices on campus. It is the first unit of this specific TEM model acquired for university laboratory use.

Housed at the Yale Institute for Nanoscience and Quantum Engineering, (YINQE) the microscope can provide clear images of objects as small as 0.2 nanometers -- less than 1/100,000th the width of a human hair -- and also identify the specific atoms and molecules in samples.

The device is expected to be especially helpful to researchers in engineering, applied physics, chemistry, and geology and geoscience, and to serve as an important tool for advances in quantum computing, energy and sustainability research, and nearly all aspects of materials science.

"Our most recent acquisition of a powerful and versatile transmission electron microscope puts at the disposal of hundreds of Yale researchers capabilities formerly unavailable within a hundred miles of this campus," said Paul Fleury, a professor of applied physics who is the institute’s director. "Thanks to substantial and sustained support from the Yale Provost’s Office, and the outstanding leadership of YINQE’s facilities director, Michael Rooks, the laboratory now provides a full suite of state-of-the-art characterization facilities."

The institute, established in 2006 and located at the Malone Engineering Center, fosters collaboration among scientists in various disciplines who work on nano-scale research projects.

"When constructing structures on the nanometer scale, it is essential be able to see what one is doing," said Steve Girvin, deputy provost for science and technology and a professor of physics and applied physics. "This instrument provides that capability, not only producing images of the atomic structure but also providing valuable information on local chemical composition at each point in the image."

Yale has other transmission electron microscopes, including a relatively new one at the School of Medicine, but these are tailored for examining soft-tissues and other samples containing water. YINQE’s new microscope is configured for examining natural and fabricated hard materials, such as crystals, semiconductors and carbon nanotubes.

The new TEM also conducts chemical analysis more efficiently -- about 10 times faster than the medical school TEMs, according to Rooks, who holds a 1987 Yale Ph.D. in applied physics.

"If you grow a crystal and the elements have reconfigured in a bad way, you’d like to be able to see that," he said.

Installed last fall, the microscope is now in use by a small number of researchers previously familiar with its operation. Rooks, who oversees YINQE’s research equipment, said institute personnel will train on the new machine early this year and quickly turn to training additional interested researchers. Like other instruments in the YINQE laboratory, the TEM will be available to any qualified researcher at an hourly fee.

"The arrival of the new TEM will greatly enhance our research," said Lisa Pfefferle, a professor of chemical engineering whose lab designs new nanomaterials for energy, electronic, and biological applications. "Before we had no way of measuring elemental composition on this length scale."

Gayatri Keskar, a postdoctoral student in Pfefferle’s lab, said the new microscope is easy to use and fast, reducing the time necessary for mapping a sample’s elements "from hours to minutes or seconds,, compared to standard solutions."

The new microscope is an Osirus ChemiSTEM model from FEI Co., the Oregon-based scientific instruments maker that also provided the medical school’s newest TEM. Configured with both a high-sensitivity x-ray detector and an electron energy loss spectrometer, enabling it to detect a wide range of elements, the device is also equipped with a 200 kV electron source. A TEM relies on electron beams fired through the sample under scrutiny to generate magnified images.

While the new TEM is not the only microscope at Yale with atomic-level resolution, it is the most efficient at elemental analysis.

The new TEM is housed in a 13-by-18-foot, soundproof enclosure within YINQE’s multi-room lab, a glance away from the institute’s electron-beam writing instrument and the high-resolution scanning electron microscope. The location was considered ideal for the new microscope, both because of the device’s numerous engineering applications and because the extra thick floor of the Malone Center’s basement offers stability. Minimizing vibration is essential, given the machine’s sensitivity.

Said Rooks, "If you talk too loudly, you can see your voice moving the image around."