NOVELTY - Fabricating photovoltaic device involves forming a dielectric layer on a substrate (112); forming a solder layer on the dielectric layer; annealing the solder layer to form uniformly distributed solder balls on the dielectric layer; etching the substrate using the solder balls to protect portions of the substrate to form pillars (130) in the substrate such that the pillars provide a radiation absorbing structure in the photovoltaic device; and wet etching the pillars to form cone-shaped structures to be incorporated into the photovoltaic device.    USE - For fabricating photovoltaic device (claimed) which is used in solar cell for converting the solar energy into a usable amount of electricity.    ADVANTAGE - The method is maskless, low cost and is performed at low temperatures (e.g. below 500 degrees C); exhibits improved absorption of incident radiation; and provides photovoltaic device having high efficiency.    DETAILED DESCRIPTION - Fabricating a photovoltaic device, either involves forming a dielectric layer on a substrate (112); forming a solder layer on the dielectric layer; annealing the solder layer to form uniformly distributed solder balls on the dielectric layer; etching the substrate using the solder balls to protect portions of the substrate to form pillars (130) in the substrate such that the pillars provide a radiation absorbing structure in the photovoltaic device; and wet etching the pillars to form cone-shaped structures to be incorporated into the photovoltaic device; or applying a diblock copolymer layer on a substrate; removing a first polymer material from the diblock copolymer layer to form distributed pores; depositing a pattern forming layer on a remaining surface of the diblock copolymer layer and in the pores in contact with the substrate; lifting off the diblock copolymer layer and portions of the pattern forming layer to leave portions of the pattern forming layer in contact with the substrate; and etching the substrate using the pattern forming layer to protect portions of the substrate to form pillars in the substrate such that the pillars provide a radiation absorbing structure in the photovoltaic device. An INDEPENDENT CLAIM is included for a photovoltaic device, comprising a substrate including uniformly spaced and distributed nano-scale cone-shaped pillars, where the cone-shaped pillars include black silicon.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of the substrate showing another electrode formed on the pin stack.    Substrate (112)    Pillar (130)    First electrode layer (132)    p-i-n Diode stack (134)    Second electrode (136)