We report the first efficient photoanode with a negative flatband potential, consisting ofn‐Fe2O3andn‐Si. An anodic current of ∼0.8 mA/cm2was observed at 0 V SCE in 0.1 M KOH solution under an illumination of ∼60 mW/cm2. A photocurrent rose at ∼−0.3 V SCE under the same condition. An electronbeam evaporation of Fe, followed by its oxidation at 700 °C under 5×10−2Torr was successful in obtaining an efficient photoanode. The surface structure was analyzed using x‐ray photoemission spectroscopy (XPS) and Auger‐electron spectroscopy (AES) techniques and capacitance‐voltage measurements. XPS spectra revealed that the surface structure was composed of Fe2O3‐Fe3O4‐Si. XPS signals showed that the SiO2phase also coexisted at the top surface probably due to interdiffusion of Si. Depth profiles were obtained by the AES technique.