Fabrication and structural characterization of photoanodes Device manufacturing (detail in the methods section) starts by sputtering a Ti/Au Ohmic contact at the backside of the surface cleaned Si wafer, followed by plasma-enhanced atomic layer deposition (PE-ALD) growing of titanium oxide (TiO x ) layer to passivate the surface defects . The process finishes by depositing an ultrathin NiFe alloy film with electron beam evaporation, with controlled thickness in the range between 1 nm to 8 nm.