Abstract: Electrically tunable metasurfaces including an array of subwavelength metasurface unit elements are presented. The unit elements include a stacked metal-insulator-metal structure within which an active phase change layer is included. A purely insulator, metal, or coexisting metal-insulator phase of the active layer can be electrically controlled to tune an amplitude and phase response of the metasurfaces. In combination with the subwavelengths dimensions of the unit elements, the phase and amplitude response can be controlled in a range from optical wavelengths to millimeter wavelength of incident light. Electrical control of the unit elements can be provided via resistive heating produced by flow of current though a top metal layer of the unit elements. Alternatively, electrical control of the unit elements can be provided via electrical field effect produced by applying a voltage differential between the top and bottom metal layers of the unit elements.

Abstract: Photovoltaics configured to be manufactured without epitaxial processes and methods for such manufacture are provided. Methods utilize bulk semiconducting crystal substrates, such as, for example, GaAs and InP such that epitaxy processes are not required. Nanowire etch and exfoliation processes are used allowing the manufacture of large numbers of photovoltaic cells per substrate wafer (e.g., greater than 100). Photovoltaic cells incorporate electron and hole selective contacts such that epitaxial heterojunctions are avoided during manufacture.

Abstract: Systems and methods of non-epitaxial high Schottky barriers heterojunction solar cells are described. The high Schottky barriers heterojunction solar cells are formed using non-epitaxial methods to reduce fabrication costs and improve scalability.

Abstract: Electrically tunable metasurfaces including an array of subwavelength metasurface unit elements are presented. The unit elements include a stacked metal-insulator-metal structure within which an active phase change layer is included. A purely insulator, metal, or coexisting metal-insulator phase of the active layer can be electrically controlled to tune an amplitude and phase response of the metasurfaces. In combination with the subwavelengths dimensions of the unit elements, the phase and amplitude response can be controlled in a range from optical wavelengths to millimeter wavelength of incident light. Electrical control of the unit elements can be provided via resistive heating produced by flow of current though a top metal layer of the unit elements. Alternatively, electrical control of the unit elements can be provided via electrical field effect produced by applying a voltage differential between the top and bottom metal layers of the unit elements.

Abstract: Photovoltaics configured to be manufactured without epitaxial processes and methods for such manufacture are provided. Methods utilize bulk semiconducting crystal substrates, such as, for example, GaAs and InP such that epitaxy processes are not required. Nanowire etch and exfoliation processes are used allowing the manufacture of large numbers of photovoltaic cells per substrate wafer (e.g., greater than 100). Photovoltaic cells incorporate electron and hole selective contacts such that epitaxial heterojunctions are avoided during manufacture.