UHV-HRTEM observation of Pd clusters on Pd adsorbed Si(1 1 1) 1×1 surface

Pd clusters on a Pd deposited Si(1 1 1) surface were observed by ultrahigh vacuum high-resolution transmission electron microscopy. Both the Pd adsorbed 1×1 surface layer and Pd clusters on it were visualized on the condition of an illumination beam convergence of about 3 mrad, over-focus of about −10 nm and specimen thickness less than 30 nm. Structure models for the clusters were examined so that images simulated using their models show agreement with the observed ones. It was found that the Pd trimer model, each Pd atom of which sites at the on-top of Pd atoms in the 1×1 surface layer, are consistent with the experimental results.