A nanoelectronic device includes a nanostructure, such as a nanotube or network of nanotubes, disposed on a substrate. Nanoparticles are disposed on or adjacent to the nanostructure so as to operatively effect the electrical properties of the nanostructure. The nanoparticles may be composed of metals, metal oxides, or salts, and nanoparticles composed of different materials may be present. The amount of nanoparticles may be controlled to preserve semiconductive properties of the nanostructure, and the substrate immediately adjacent to the nanostructure may remain substantially free of nanoparticles. A method for fabricating the device includes electrodeposition of the nanoparticles using one or more solutions of dissolved ions while providing an electric current to the nanostructures but not to the surrounding substrate.