In an engineering lab at the University of Puerto Rico, Mayaguez (UPRM) , a student takes pictures of a nanomaterial by controlling a microscope with a computer. What makes this scene unique is that the microscope isn’t beside the computer or even in the next room. Rather, it’s located in the basement of the UW-Madison Materials Science and Engineering Building.
Unveiled in April, the new scanning transmission electron microscope, or STEM, is one of a handful of instruments of its kind in the United States. It’s used to take high- spatial-resolution images of the atomic structure and composition of a variety of materials. The microscope’s high spatial resolution is important because the distance between atoms in most materials is two to three Ångstroms. (An Ångstrom equals 0.1 nanometer.) Previous microscopes had a resolution of two to three Ångstroms, meaning researchers could barely make out any atoms at all.
However, the new STEM has a spatial resolution of less than one Ångstrom, meaning researchers can take images that show where every atom in a piece of material is located, as well as what elements the various atoms are.
“This microscope gives us a level of instrumentation on par with the world-leading federal laboratories and research universities,” says Materials Science and Engineering Associate Professor Paul Voyles (pictured), who with Animal Sciences Professor Ralph Albrecht and Geoscience Assistant Professor Huifang Xu led the effort to bring the STEM to UW-Madison.
The STEM will aid UW-Madison researchers working on advanced metal alloys, nanoelectronic devices, catalysis, biomacromolecules and other areas. In addition to serving researchers on campus, the STEM can be operated remotely, making it a global tool. Access to a STEM is crucial for the many catalysis and nanomaterials researchers at UPRM, so the institution partnered with UW-Madison on the original acquisition grant from the National Science Foundation.
Additionally, the remote operating capabilities allow Voyles and others to train a larger number of researchers to use the STEM, further expanding its impact.