High efficiency polycrystalline silicon solar cells with conventional and selective emitters

Polycrystalline silicon solar cell emitter optimization was studied in two distinct situations. Using industrial Polix wafers with a diffused p⁺ layer at the back side, that were submitted to a special gettering process, a conventional p-doped emitter was back-etched, and a conversion efficiency of 15.6% was reached for 2×2 cm² cells. Another series of cells were made with a selective emitter, having enhanced doping under the front grid fingers and a selective emitter etchback between the fingers: in this case, cell efficiency was found to be improved as compared to the case of homogeneous emitters