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| Engineers at Ohio State University and their colleagues took this image to study the interaction of atoms at the interfaces between layers of semiconductor materials. They used an electron microscopy technique known as z-contrast, which identifies atoms in a material by scattering electrons off the surface. The very bright atoms in the middle are germanium; dimmer silicon atoms can be seen to the left. Silicon dioxide cannot be viewed with this technique, so atoms of that compound are invisible to the right. To visualize the silicon dioxide, the engineers used a complimentary method called EELS, or electron energy loss spectroscopy, which transmits electrons through a material. The results showed that the atoms at the interfaces between layers matched up perfectly to form what researchers call an “atomically sharp” interface. Image courtesy of Ohio State University. |