Clearest images to date taken of silicon surface

17 Jun 2002

Silicon is one of the most common elements on earth, and yet its surface structure is probably the most complicated of all --- a three-layered geometric construction of atoms with tiny holes at its peaks. Researchers at Northwestern University and the NEC Corporation in Japan have made the clearest images to date of this complex surface.

Using a High Resolution Electron Microscope (HREM), the researchers have developed images that reveal a beautiful symmetry when the jagged surface is seen from above. The images, which first appeared in Physical Review Letters, will be displayed this fall as part of a permanenet exhibition at the Research Institute of Discrete Mathematics at the University of Bonn.

The images confirm the model of the surface's structure first proposed by K. Takayanagi and associates in 1985. That model describes a basic unit of 112 atoms arranged in a parallelogram of three layers, with 12 atoms on the top layer which all rest on atoms in the next two layers. These 12 atoms appear as black in the High Resolution Electron Microscope (HREM) imagery.