We report here on recent measurements made on our Pt–Cu2O–Cu diodes, annealed at an air pressure of 1 to 2 Torr, which we interpret as due to double injection, i.e. injection of holes from the platinum electrode and injection of electrons from the copper–Cu2O junction into the single crystal Cu2O region. The measurements discussed here include the forward I–V characteristics at various temperatures, current vs. thickness relationship at constant voltage, the effect of photo-memory on the I–V characteristics, and the discovery of a negative resistance regime at below room temperature at sufficiently high injection levels. The analysis of the temperature dependence of the current in the ohmic and the [Formula: see text] regimes, together with the effect of photomemory on the I–V characteristics enable us to identify the [Formula: see text] regime as the Ashley–Milnes regime with field dependent mobility.