Growth and Morphology of Ni Films on Cu(111)

Conventional and manipulated molecular beam epitaxy (MBE) of Ni on Cu(111) was studied by helium atom scattering and low-energy electron diffraction over a wide temperature range. During conventional MBE at low temperatures, three-dimensional rough growth is observed. The films consists of pyramids with {445} microfacets. At room temperature, growth leads to smoother films which consist of hexagonal structures. At high temperatures, the films partially grow via stepflow. To improve the film quality, growth manipulation methods, based on the concept of two mobilities, were applied. By temperature reduction or rate enhancement during nucleation and pulsed ion beam assisted deposition, the island number density was artificially increased and smoother growth of the first layers was promoted in most cases. However, temperature reduction during nucleation failed to promote better growth, which is explained by an unusual annealing behaviour of the nuclei. The morphology of films grown by manipulated and conventional MBE are compared.