On the influence of sub-wavelength Al/Si interface roughness on the efficiency of crystalline Si-solar cells

The effect of nano-planarization of pyramidally textured wafer surfaces by wet-chemical treatment on solar cell parameters is investigated. The obtained significant increase of the photocurrent at long wavelengths is attributed to the improvement of the back side reflectance, whereas the higher fill factor is assigned to a lowering of the back contact resistance. Theoretical estimate and numerical modeling support these assumptions.

► The effect of nano-planarization of pyramidally textured wafers is investigated.
► The surface smoothening is achieved by wet chemical treatment.
► Increase of photocurrent is attributed to improvement of back side reflectance.
► This is due to reduction of Al/Si interface microscopic roughness.
► The higher fill factor arises from lower back contact resistance.