IN-SITU AFM OBSERVATIONS OF OXIDE FILM FORMATION ON CU(111) AND CU(100) SURFACES UNDER AQUEOUS ALKALINE-SOLUTIONS

An in situ electrochemical atomic force microscope (ECAFRA) has been used to investigate the formation of oxide films on Cu(111) and Cu(100) surfaces under NaOH solutions. It has been demonstrated that the clean unreconstructed Cu(111)- and Cu(100)-(1 X 1) surfaces could be exposed under NaOH solutions at an electrode potential more negative than - 0.5 V versus NHE. After the formation of the Cu2O layer, Cu2O(111)- and Cu2O(100)-(1 X 1) surfaces terminated by oxygen atoms have been observed in the potential range between - 0.2 and - 0.02 V. We have found a tilted epitaxy as well as parallel epitaxial relationships of Cu2O(111)[1 $($) over bar$$ 10]//Cu(111)[1 $($) over bar$$ 10] and Cu2O(100)[001]//Cu(100)[0 ($$$) over bar 11] on an atomic level.