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 dif fraction over a wide temperature range. During conventional MBE at low temperatures, three-dimensional rough growth is observed. The films c onsists of pyramids with {445} microfacets. At room temperature, growt h leads to smoother films which consist of hexagonal structures. At hi gh temperatures, the films partially grow via stepflow. To improve the film quality, growth manipulation methods, based on the concept of tw o mobilities. were applied. By temperature reduction or rate enhanceme nt during nucleation and pulsed ion beam assisted deposition, the isla nd number density was artificially increased and smoother growth of th e first layers was promoted in most cases. However, temperature reduct ion during nucleation failed to promote better growth, which is explai ned by an unusual annealing behaviour of the nuclei. The morphology of films grown by manipulated and conventional MBE are compared. (C) 199 8 Elsevier Science B.V.