An electrochemical-deposition apparatus includes an electrode array, a photoconductor, an electrically conductive layer, an electromagnetic-radiation emitter, an electric-power source, and a controller. The controller is configured to direct electric power to be supplied from the electric-power source to the electrically conductive layer and direct the electromagnetic-radiation emitter to generate electromagnetic radiation. When the electric power is supplied to the electrically conductive layer and when the electromagnetic radiation is generated, the photoconductor is illuminated at a first radiation level and a first level of electric current is enabled through the photoconductor and the at least one deposition electrode. When the electric power is supplied to the electrically conductive layer and when the electromagnetic radiation is generated, the photoconductor is illuminated at a second radiation level and a second level of electric current is enabled through the photoconductor and the at least one deposition electrode.

Methods for processing a silicon solar cell are disclosed herein. Exemplary methods may comprise preparing an ionic liquid comprising aluminum chloride (AlCl3) and an organic halide, patterning a partially processed silicon solar cell to expose an n-type surface of a p-type silicon substrate, bringing the n-type surface into contact with the ionic liquid, wherein the n-type surface does not comprise a seed layer, illuminating the n-type surface, wherein the illumination passes through the ionic liquid, is generated at least partially by a light source, and a photo-generated current is generated by the illumination, while illuminating the n-type surface with the light source, applying a current between an anode and a cathode to generate an applied current, and depositing aluminum onto the n-type surface via a light-induced electroplating process, wherein the light-induced electroplating process utilizes the applied current that does not exceed the photo-generated current generated by the illumination.

A method for coating a substrate with a CoPi modified BiVO.sub.4/WO.sub.3 heterostructure film includes direct current reactive sputtering tungsten (W) onto a substrate in a gaseous mixture containing oxygen to form a tungsten trioxide (WO.sub.3) film, direct current reactive sputtering bismuth (Bi) onto the tungsten trioxide (WO.sub.3) film in a gaseous mixture containing oxygen to form a dibismuth trioxide (Bi.sub.2O.sub.3) film, drop-casting a vanadyl acetylacetonate solution onto the Bi.sub.2O.sub.3 film and heating at a temperature of at least 450 C. in ambient air to convert the Bi.sub.2O.sub.3 film to a BiVO.sub.4 film, and photoelectrochemically coating the BiVO.sub.4 film with a cobalt-phosphate (CoPi) to form a modified film on the surface of the substrate. A photoanode containing the CoPi modified BiVO.sub.4/WO.sub.3 heterostructure film prepared by the method, and its application in water splitting.