Structure of Al deposits on nanometer-size islands of aluminum-oxide

Because of the immense structural mismatch between a crystal and a quasicrystal, the aluminum-oxide domains that grow on the pentagonal surface of icosahedral Al-Pd-Mn at high temperatures are in the order of a few nm large. Here, we exploit the small lateral extension of the oxide domains to grow crystalline Al particles in the same size-region by vapor deposition on them. Low-energy-electron diffraction and secondary-electron imaging investigations show that the nanocrystals expose their (1 1 1) faces parallel to the pentagonal surface of the quasicrystal, while the in-plane orientation of the crystallites is random. Spot-profile analysis of the diffracted beams indicate that the Al nanocrystals grow in 3 nm large domains up to a deposition thickness of 51 monolayers.