Low-cost rear side floating junction solar-cell issues on mc-Si

Rear side floating junction solar cells with localised contacts often show parasitic shunting losses. For p-type material, this is due to tunnelling that takes places between the passivating n+n+-type rear junction and the p+p+-type back surface field region underneath localised rear contacts. To avoid this, the rear metallisation and the passivation layer should electronically be separated. Alternatively, the (induced) doping concentration of these layers could be optimised. This paper discusses the constraints met upon incorporation of such lowly recombinative structures into a low-cost solar cell process on multi-crystalline Si (mc-Si) material.