Abstract
We compare the growth of a Bi thin film on the ten-fold surface of the decagonal Al-Ni-Co quasicrystal at different substrate temperatures and fluxes using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The growth at 29 K leads to the formation of a quasicrystalline monolayer, consistent with the results obtained at 300 K. Further deposition at low temperature produces pseudocubic islands with {100} surface orientation. The islands have two or four atomic layer heights. Both STM and LEED measurements reveal that there is a transition from the pseudocubic {100} film to the hexagonal {0001} surface orientation at coverage (θ) 4 < θ < 6 ML. The hexagonal domains are oriented along the high symmetry directions of the substrate. Growth at room temperature with different fluxes results in different island-height distributions. High flux predominantly produces islands of uniform four-layer high islands, whereas low flux yields islands of varying heights, yielding a rough film morphology. The two-layer high islands are found to be more stable at low temperature than at room temperature.
Acknowledgements
This work was supported by the Engineering and Physical Sciences Research Council (Grant No. EP/D071828/1 and EP/DO5253X/1). The European Network of Excellence on ‘Complex Metallic Alloys’, Contract No. NMP3-CT-2005-500145, and the Agence Nationale de la Recherche, Reference No. ANR-07-Blan-0270, are thanked for their financial support. We thank R. McGrath and J. Smerdon for helpful discussions.