The interface between the Cu and Cu2O is investigated by means of the density functional theory. Several parameters representing the effects of the electronic structure of the boundary are derived. They show that there exist a continuous chemical bonding across the Cu-Cu2O system. This is not compatible with the usual Schottky barrier model and because of that a new qualitative scheme of the band alignment is proposed. A possible way for a quantitative interpretation of the experimental current-potential data in the framework of the electronic structure concept is considered. (C) 2005 Elsevier Ltd. All rights reserved.