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Semi-conductors with mobile acceptors or donors show a new type of I-V relations. This paper presents experimental results for solid state devices based on copper oxide, found to be Cu 2 O, which exhibit these I-V relations. The cells examined are Cu|Cu 2 O|In and Cu|Cu 2 O|Ag and similar ones tested at room temperature. The measured I-V relations are different from those reported for the same type of cells in the past, which were explained to be fixed by a Schottky barrier Cu|Cu 2 O. We find that the I-V relations relax over a long time which we claim is due to ion redistribution. The new I-V relations can then be explained by assuming that Cu 2 O is a mixed-ionicelectronic-conductor and adopting a theory developed by us in the past and modified to be applicable to the relevant defect model here. In this case the contribution of Schottky barriers is insignificant.

Current-voltage relations, electric field, and charge distribution profiles are calculated for a device in which the dopants are mobile. The thin film limit is discussed. The model solved is restricted to: (a) mobile holes and acceptors, (b) steady state, and (c) metal electrodes which block the ionic current. The solution is expressed as a series expansion in the small parameter δ=L/λD, where L is the sample thickness and λD is a Debye length. The second order of the series expansion is found to vanish, thus the corrections to the leading order appear only in the third term. The approximated analytic solution agrees with numerical results from a previous publication up to the quite high value of δ=1. The leading order in the I-V relations and in the hole distribution is independent of the acceptor motion. This implies that for thin devices of this form any motion of the dopants may be neglected and that dopants need not be limited only to those which exhibit low diffusion constants. Rectification is observed as long as asymmetry is introduced by two different contact potentials. This holds whether the contacts lead to depletion or accumulation.

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