An interposer device comprising an interposer substrate; a plurality of conducting vias extending through the interposer substrate; a conductor pattern on the interposer substrate, and a nanostructure energy storage device. The nanostructure energy storage device comprises at least a first plurality of conductive nanostructures formed on the interposer substrate; a conduction controlling material embedding each nanostructure in the first plurality of conductive nanostructures; a first electrode connected to each nanostructure in the first plurality of nanostructures; and a second electrode separated from each nanostructure in the first plurality of nanostructures by the conduction controlling material, wherein the first electrode and the second electrode are configured to allow electrical connection of the nanostructure energy storage device to the integrated circuit.