Growth, alloy formation and reaction with oxygen of Ag and Au submonolayers on W(1 1 0) studied by valence band and core level photoemission

We have studied epitaxial submonolayers of Ag and Au deposited one after another onto W(1 1 0) at room temperature and subsequently annealed at 600 K. Photoemission spectroscopy of valence bands and the Ag3d5/2 core level has been used to monitor two-dimensional alloy formation. The extent of alloying depends on the order of deposition, composition and annealing. We have also studied the reaction of alloy surfaces to exposure of molecular oxygen at 300 and 600 K.