ABSTRACT
The influence of the different material parameters on solar cell efficiency is experimentally investigated with a high-efficiency solar cell structure which is almost solely limited by the properties of the silicon under investigation and not by cell structure properties such as surface passivation or optics. A microscopic model to qualitatively explain the results was proposed by Kittler and Seifert in which impurities are either accommodated in the strain field of dislocations, where they are weakly bound and can be gettered, or in the core region of a dislocation, from where they cannot be gettered. Dislocations limit the carrier lifetime, the crucial parameter for crystalline silicon solar cells, and the gettering efficiency of phosphorus diffusions. This shows that the cell structure is not restricted to special material and high-efficiency solar cells can be fabricated from multicrystalline silicon if an appropriate cell process is applied.
