NOVELTY - Fabricating solar cell involves providing a doped substrate (202); depositing a monolayer of spheres onto substrate, where spheres comprises nanospheres, and/or microspheres; trimming the spheres to introduce space between individual spheres in the monolayer; using the trimmed spheres as a mask to pattern wires (502) in the substrate, the wires comprises nanowires, and/or microwires; forming a doped emitter layer on the patterned wires; depositing a top contact electrode over the emitter layer (702); and depositing a bottom contact electrode on a side of the substrate opposite the wires.    USE - For fabricating a nanowire/microwire-based solar cell (claimed).    ADVANTAGE - The method provides an improved solar cell fabrication technique that lower production costs. The present techniques provide a fabrication process that employs top-down nanospheres/microsphere lithography, thereby avoids standard processes such as electron beam or ultra-violet lithography which are limited by low throughput and thus prohibitively expensive. Nanosphere/microsphere lithography fabrication techniques provide a simple, low cost and high throughput technique to define large scale nanowire and/or microwire structures. The present nanosphere/microsphere lithography fabrication techniques are free from metal catalysts that can be very detrimental to solar cell performance. The above technique offer greater flexibility in controlling the size (diameter and height) of the nanowires and/or microwires, as compared to conventional bottom-up techniques (such as VLS nanowire growth techniques where the nanowires are grown by chemical vapor deposition process-metal catalyst). The nanosphere/microsphere lithography is a viable technique to realize nanowires/microwires in large scale with low cost and high throughput necessary for solar cell production.    DESCRIPTION OF DRAWING(S) - The figure shows a formation of an emitter layer by diffusion.    Substrate (202)    Pattern wires (502)    Emitter layer (702)    Dopant source (1002)