The need for cost reduction requires using less raw material and cost-effective processes without sacrificing the conversion efficiency. We propose a metal-free light trapping scheme for absorption enhancement in ultra-thin silicon wafers: black silicon and alkaline pyramidal textures for state-of-the-art light in-coupling at front side and efficient light scattering at back side, respectively, and dielectric Distributed Bragg Reflector for omni-directional rear reflectance. Measured absorptances of wafers with different thickness showed a spectral behavior up to 98% of 4n2 classical absorption limit (400 nm - 1200 nm). Our textured wafers were also electrically investigated by measuring effective carrier lifetime. We calculated the implied photo-generated current density and open-circuit voltage as function of wafer thickness, finding that (i) fabricated 80 μm thick wafer can potentially generate a conversion efficiency higher than 21% and (ii), by extrapolating the efficiency trend down to 10 μm, conversion efficiency peaks for thicknesses between 40 and 60 μm.