New optical features to enhance solar cell performance based on porous silicon surfaces

Electrochemical etching is used to fabricate porous silicon (PS) surfaces for both sides of the Si wafer. The effect of PS on performance of Si solar cells is investigated and the reflected mirrors are manipulated to enhance solar cell efficiency. The process is promising for solar cell manufacturing due to its simplicity, lower cost and suitability for mass production. The PS surface has discrete pores and short-branched pores on the polished wafer side. In contrast, the etched backside of the wafer has smaller pore size, with random pores. PS formed on both sides has lower reflectivity value compared with results in other works. Solar cell efficiency is increased to 15.4% with PS formed on both sides compared with the unetched sample and other results. Using empirical models, the optical properties of the refractive index and the optical dielectric constant are investigated. The porous surface texturing properties could enhance and increase the conversion efficiency of porous Si solar cells. The obtained results are in agreement with experimental and other data. (C) 2011 Elsevier B. V. All rights reserved.