Primary voltaic sources include nanofiber Schottky barrier arrays and a radioactive source including at least one radioactive element configured to emit radioactive particles. The arrays have a semiconductor component and a metallic component joined at a metal-semiconductor junction. The radioactive source is positioned proximate to the arrays such that at least a portion of the radioactive particles impinge on the arrays to produce a flow of electrons across the metal-semiconductor junction. Methods of producing voltaic sources include reacting at least one carbon oxide and a reducing agent in the presence of a substrate comprising a catalyst to form a solid carbon product over the substrate. Material is disposed over at least a portion of the solid carbon product to form a nanofiber Schottky barrier array. A radioactive source is disposed adjacent the nanofiber Schottky barrier array.

Provided is a method for separating a nanogenerator, which includes laminating a buffer layer on a sacrificial substrate, making a nanogenerator on the buffer layer, laminating a metal layer on the nanogenerator and separating the nanogenerator from the buffer layer. Here, a nanogenerator is separated by using a stress difference between the sacrificial substrate and the metal layer, instead of an existing method in which a nanogenerator is separated from the sacrificial substrate by means of wet etching or the like. In particular, according to a difference between a tensile stress at the metal layer such as nickel and a compressive stress at the lower silicon substrate, the nanogenerator is intactly separated from the silicon oxide layer serving as a buffer layer. Therefore, the nanogenerator may be separated from the sacrificial substrate in a mechanical way, which is safer and more economic in comparison to an existing chemical separation method using an etching solution. Further, it is also possible to avoid a damage of the nanogenerator caused by an etching solution.

A magnetic generator may be disclosed. The magnetic generator may include one or more permanent magnets which may function in one or more ways in combination with a dielectric elastomer to efficiently produce electricity. Electricity may be produced directly by the magnets, through mechanical means as driven by the magnets, by piezoelectric means, or as desired to maintain peak efficiency. Further, systems to retain excess energy for later use, such as a flywheel or a battery may be employed.