Stoichiometric and Non-Stoichiometric Cu2O(111) Single Crystal Surfaces

X-ray photoelectron spectroscopy (XPS) was used to investigate a non-polar Cu2O(111) single-crystal surface following two different preparations. The first surface, prepared by Ar-ion bombardment and annealing to 1000 K in vacuum, is nearly stoichiometric and exhibits a (1 × 1) LEED periodicity. Exposure to large doses of dissociated hydrogen gas produces the second oxygen-deficient surface which exhibits a (3 × 3) R30° LEED periodicity associated with 1/3 of an atomic layer of oxygen vacancies. There are no significant differences observed in normal emission XPS, in agreement with simulations that suggest the observed compositional changes should be smaller than the associated experimental error.