LEED - Low Energy Electron Diffraction

(Omicron MCP LEED)

LEED is used to study the symmetry, periodicity and atomic arrangement of solid crystal surfaces and thin films. The LEED pattern symmetry, peak position and intensities give direct information on surface lattice parameters and the position of atoms in the surface unit cell.

As seen in the graph below, a beam of low energy electrons of 10-500 eV are impinging onto a substrate surface and ~ 1 % are elastically reflected to a fluorescence screen. A diffraction pattern can be observed and allows the reconstruction of the crystalline structure of the probe material. In the example it is Lithiumfluoride.

The NanoSYD LEED is a special channelplate LEED wich allows for the observation of the crystal structure of soft organic thin films, see example.

LEED image from crystalline ultrathin heptane thiole film on Au at 49 eV electron energy