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Lehigh’s renowned microscopy labs expand their focus

A prototype of the JEM-ARM200F scanning transmission electron microscope. The new Lehigh instrument will be customized to enable atomic-level composition analysis while improving stability, data acquisition speed and image quality.

Lehigh’s world-renowned Nanocharacterization Laboratory will achieve a major upgrade this year with the installation of a customized state-of-the-art scanning transmission electron microscope (STEM). The instrument will replace an advanced aberration-corrected electron microscope installed in 2004.

The multi-million dollar instrument will be purchased with a $1.2 million Major Research Instrument (MRI) Program grant awarded by the National Science Foundation in 2010 to a research group led by Masashi Watanabe, associate professor of materials science and engineering. Matching funds have been provided through the sale of the older microscope and by Lehigh as well.

The new microscope, a JEM-ARM200F, is a new model of aberration-corrected STEM that will include additional customized features specified by the Lehigh team.

The features include the latest, most sophisticated detectors for electron energy loss spectroscopy (EELS) and X-ray energy dispersive spectroscopy (XEDS), which will allow composition analysis at atomic resolution while improving stability, data acquisition speed and image quality, says Watanabe, principal investigator on the grant.

Setting a new standard

Similar JEM-ARM200F instruments are being installed at several other universities, says Watanabe, “but they lack many of the additional special features specified for Lehigh’s new microscope.

“I’m sure this new instrument configuration will become standard in the next couple of years, and we should be proud of being the first university to have it.”

The JEM-ARM200F, which will take about a year to build at the JEOL factory in Tokyo, will likely be delivered near the end of 2011, says Christopher Kiely, professor of materials science and engineering and director of the Nanocharacterization Lab and Lehigh Microscopy School.

The original microscope—a JEOL 2200FS STEM—was the first aberration-corrected microscope at a U.S. university, says Kiely, co-principal investigator on the MRI grant. Such microscopes are designed to obtain atomic-resolution images and compositional analyses of materials.

“The current instrument has worked very well on both these fronts,” Kiely says, “but the technology has improved considerably since 2004.

“We are getting an instrument that will be able to image atoms even more clearly and allow us to break new barriers in compositional analysis,” Kiely says.

A new range of materials

The JEM-ARM200F can be used at lower voltages, which will allow researchers to study a wider range of materials. The current instrument, which operates at 200 kV, can only analyze materials that are quite robust.

“If you want to look at electron beam-sensitive materials or biological samples, you really need to be able to work at lower energies,” Kiely says. The JEM-ARM200F can operate in the 60-to-200 kV range, allowing researchers for the first time to properly characterize more delicate materials such as nanostructured carbon materials (nanotubes, graphene), nanoporous crystalline solids (zeolites), polymers, chalcogenide glasses and biomaterials with atomic-scale resolution.

The microscope will be showcased at the annual Lehigh Microscopy School, a summer program attended by more than 5,500 scientists, engineers and technicians from around the world since 1970. Research enabled by the instrument will also be used in undergraduate and graduate classes.

The Lehigh team submitted the NSF proposal last April and was notified in October that it had received the grant.

“We were among more than 30 teams that submitted an MRI grant for a TEM, but were the only one awarded a grant during this particular funding cycle,” Watanabe says.

 

Story by Amy White

Posted on Monday, February 28, 2011

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