Growth of copper and vanadium on a thin Al2O3-film on Ni3Al(111)

The growth of different metals on thin Al2O3-filins on Ni3Al(111) was investigated using scanning tunneling microscopy (STM). These thin alumna films are well ordered showing two superstructures, which appear in the STM images at different bias voltages. These supers true Lures, with periodicities of 2.6 and 4.5 nm, respectively, are shown here to govern the nucleation of the deposited metals. Copper clusters grow on these nucleation centers only at room temperature, Higher temperatures lead to an increase of the cluster size and the loss of order. In turn, vanadium forms ordered cluster arrays at room and higher temperature. Due to the stronger metal-oxide interaction compared to copper vanadium forms smaller clusters at low and high coverages, which do not show any ripening after annealing. Based on these observations, Al2O3-films on Ni3Al(111) prove to be an interesting template for the fabrication of periodic cluster arrays. (C) 2001 Elsevier Science B.V. All rights reserved.