Transmission electron microscopy study of platinum clusters on Al2O3/NiAl(110) under the influence of electron irradiation

Using transmission electron microscopy we have studied the influence of the electron beam in an electron microscope onto platinum clusters deposited o n a thin single crystalline gamma-Al2O3 film grown by oxidation of NiAl(110 ). At electron current densities below j approximate to 1 A/cm(2) no influe nce is observed. Movement and coalescence of clusters occur at electron bea m current densities between j = 2 and some 10 A/cm(2). For current densitie s around j = 50 A/cm2 decoration of steps takes place. Further increase to j = 100 A/cm(2) and above induces drilling of holes into the substrate by c lusters. At such current densities also melting of the clusters may occur. Due to the heat capacity of the system the result does not only depend on t he electron current density but also on the irradiation time. (C) 1999 Amer ican Vacuum Society. [S0734-2101(99)04202-5].