NOVELTY - Photovoltaic device (200) operable to convert light to electricity, comprises a substrate (205), one or more structures (220) essentially perpendicular to the substrate, a reflective layer (250) disposed on the substrate, and one or more junctions conformally disposed on the structures.    USE - The photovoltaic device is useful in a photo detector for converting light to electricity (all claimed). The photovoltaic device is useful for space applications such as in satellites, spacecrafts and space stations, as main or auxiliary power sources for land vehicles, marine vehicles (boats) and trains, and other applications including road signs, surveillance cameras, parking meters, personal mobile electronics preferably cell phones, smart phones, laptop computers, and personal media players.    ADVANTAGE - The photovoltaic device is solid state device that converts the energy of sunlight directly into electricity in a simple manner.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) making the photovoltaic device comprising generating a pattern of openings in a resist layer using a lithography technique, where locations and shapes of the openings correspond to location and shapes of the structures, and forming the structures by etching the substrate, and depositing the reflective layer to the substrate;    (2) converting light to electricity comprising exposing the photovoltaic device to light and drawing an electrical current from the photovoltaic device;    (3) a photo detector comprising the photovoltaic device, where the photo detector is configured to output an electrical signal when exposed to light; and    (4) detecting light comprising exposing the photovoltaic device to light and measuring an electrical signal from the photovoltaic device.    DESCRIPTION OF DRAWING(S) - The figure shows a crosssectional view of a photovoltaic device.    Photovoltaic device (200)    Substrate (205)    Structures (220)    Metal layer (240)    Reflective layer. (250)