Growth of copper and vanadium on a thin Al 2O 3-film on Ni 3Al(111)

Abstract

The growth of different metals on thin Al 2O 3-films on Ni 3Al(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 superstructures, 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, Al 2O 3-films on Ni 3Al(111) prove to be an interesting template for the fabrication of periodic cluster arrays.