Further observations of coherent scattering of hot electrons in thin gold films

The emission of hot electrons through the surface of electro-formed vacuum-deposited thin-film cathodes of Au-SiO x -Au has been studied. In the lower voltage range (<20 V) coherent scattering from pinhole edges in the Au counter-electrode was observed. For higher voltages (20-70 V) multilayer structures were necessary to avoid dielectric breakdown and in such samples coherent scattering through the top surface of the Au film from the (111), (200) and (220) planes was observed. The radii of emission patterns and the threshold voltages for the observation of diffraction from a particular set of planes, were in agreement with existing theory.