n-Type cuprous oxide was synthesized by controlling the bath pH of the electro-deposition. Thereafter, cuprous oxide films were annealed in nitrogen at different temperatures. The electrical properties of n-type cuprous oxide films before and after annealing were studied by the capacitance-voltage measurements. By analysis of the Mott-Schottky curves, it was found that the carrier concentration of cuprous oxide films varied with the deposition bath pH and the annealing temperature. Also, the flat-band potential shifted with the increasing annealing temperature. (C) 2011 Elsevier B.V. All rights reserved.