n‐type silicon solar cells with surface‐passivated screen‐printed aluminium‐alloyed rear emitter

Aluminium‐doped p‐type (Al‐p + ) silicon emitters fabricated by means of a simple screen‐printing process are effectively passivated by plasma‐enhanced chemical‐vapour deposited amorphous silicon (a‐Si). We measure an emitter saturation current density of only 246 fA/cm 2 , which is the lowest value achieved so far for a simple screen‐printed Al‐p + emitter on silicon. In order to demonstrate the applicability of this easy‐to‐fabricate p + emitter to high‐efficiency silicon solar cells, we implement our passivated p + emitter into an n + np + solar cell structure. An independently confirmed conversion efficiency of 19.7% is achieved using n‐type phosphorus‐doped Czochralski‐grown silicon as bulk material, clearly demonstrating the high‐efficiency potential of the newly developed a‐Si passivated Al‐p + emitter. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)