Porous silicon/NaOH texturization surface treatment of crystalline silicon for solar cells

• We report the effect of porous silicon/NaOH texturization on multicrystalline and monocrystalline silicon.
• Minority carrier lifetime enhancement was attributed to the oxide and hydrogen passivation produced by porous silicon.
• Porous silicon reduces the recombination velocity at the grain and grain boundery.
• The internal quantum efficiency and the conversion efficiency were improved.

Crystalline silicon surface texturing is one of the important issues of modern silicon solar cells efficiency improvement. In this work an attempt has been made to obtain a well-textured multicrystalline silicon and monocrystalline silicon surface through two different approaches. The first with standard alkaline (NaOH) solution, the second is based on a combination of formed structures obtained in NaOH and stain etching treatment in acid (HF/HNO3/H2O) solution. effect of texturisation based on these two methods on the surface morphology of Si wafers as well as on the optical and optoelectronic properties are presented in this paper. Extensively study of the surface morphologies evolution of Si wafer has been carried out and correlate to the reflectance, the effective lifetime, the internal quantum efficiency (IQE) maps and current–voltage (I–V) characteristics change before and after surface treatment.