TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The photovoltaic device comprises at least two junctions conformally disposed on the structures. The reflective layer is non-planar. The junctions are electrically connected in series. The substrate is an electrically insulating material. The substrate comprises glass, and/or polymer. The substrate is flexible or transparent. The structures have the same composition as the substrate. The structures are cylinders or prisms with a crosssection comprising elliptical, circular, rectangular, and polygonal crosssections, strips, or a mesh. The structures are cylinders with diameters of 0.2-10 mu m, heights of 2-50 mu m, a center-to-center distance between two closest pillars of 0.5-20 mu m. The top portion of the structures is rounded or tapered. The junctions are a p-i-n junction, a p-n junction, and a heterojunction. The junctions comprise: a heavily doped p type semiconductor material layer and a heavily doped n type semiconductor material layer, and optionally an intrinsic semiconductor layer sandwiched between the heavily doped p type semiconductor material layer and the heavily doped n type semiconductor material layer; a microcrystalline semiconductor material; and a semiconductor material comprising silicon, germanium, group III-V compound materials, group II-VI compound materials, and quaternary materials. The first junction of the two or more junctions has a smaller band gap than a second junction of the two or more junctions, where the first junction is closer to the structures than the second junction. The photovoltaic device further comprises: at least one an electrically conductive layer disposed between the structures and one of the two or more junctions, and/or layer disposed between a pair of neighboring junctions of the two or more junctions; and a cladding layer. The cladding layer is: substantially transparent to visible light with a transmittance of at least 50%; made of an electrically conductive material; a transparent conductive oxide; a material comprising indium tin oxide, aluminum doped zinc oxide, zinc indium oxide, silicon nitride, aluminum oxide, hafnium oxide and zinc tin oxide; and configured as an electrode of the photovoltaic device. The cladding layer has a thickness of 10-500 nm. The reflective layer is an electrically conductive material and an electrode of the photovoltaic device. The reflective layer has a reflectance of at least 50% for visible light, and a thickness of 20-500 nm. The structures are formed by deep etch. The electrical signal is an electrical current, an electrical voltage, an electrical conductance and/or an electrical resistance. The bias voltage is applied to the structures in the photovoltaic device. Preferred Method: The method further comprises tapering or rounding a top portion of the structures.