Scanning Transmisson Electron Microscopy
P.E. Batson and M.J. Lagos
We can now make an electron beam that is about the size of a hydrogen atom, and can actually place that beam on or between atoms within materials to examine how they are put together, how they might function in a device, how they might be used to measure biological activity, or hasten a chemical reaction. The image above shows the positions of columns of atoms in an interface between two metal oxide structures.We also can perform very simple experiments to understand how materials, in general, act at very short times. Atoms and molecules move about and vibrate at very high speeds. We can now, for the first time, visualize the behavior of very small structures at atto-second time scales in an electron microscope, and plan experiments to test these ideas. The film clip at the upper right is a calculation of the forces acting on a 2 nm-sized gold sphere during the passage of a fast electron in the STEM. These forces change dramatically during a few atto-seconds, inducing changes in the nano-particle that inform us about how such structures might be used for energy-gathering, catalysis and information transfer.
We acknowledge the financial support of the Department of Energy, Basic Energy Sciences (DOE project #DE-SC0005132) for work on Electron Beam Induced Forces, and the National Science Foundation MRI #0959905 for the instrumental development.
Phonon Spectra in SiO2 at ~150 meV
Nion UltraSTEM at Rutgers