The semiconductor properties of the Ag2O film formed on silver electrodes in 1 M NaOH solution have been investigated by a photoelectrochemical method. The bandgaps and flatband potential of the film were determined. The results of in situ Raman spectroscopy proved that the photo-oxidation process of Ag2O occurs at potentials higher than the flatband potential of 0.23 V vs. Hg/HgO, 1 M OH- electrode.