Abstract X-ray Photoelectron spectroscopy (XPS) was used to investigate the Pd particle formation on Al 2O 3 substrates. Palladium was deposited step by step in situ using an electron beam evaporator on single crystalline alumina specimens which had been cleaned by heating in air. The (0001), (1–102) and (11–20) orientations of alumina were used for Pd deposition with no further treatment. In addition, the (0001) and (1–102) substrates were also Ar ∗ ion sputtered before deposition, to change the surface stoichiometry and order. The Pd growth process was monitored by means of the modified Auger parameter and the Full Width at Half Maximum of the Pd3d 5 2 peak. The results obtained on the different substrates are compared and the influence of the substrate on the Pd particle growth is discussed.