ABSTRACT
This chapter describes a composite of unique processes which aims at producing a low-cost high-purity silicon for solar cell manufacturing. Two kinds of method to produce silicon solar cell feedstock material are investigated although their development stages are quite different. There is of course an economic advantage to using ribbons as against ingots but the ribbon-pulling techniques are much less mature and most of them still have to be proved viable before being industrialized. Moreover, bulk growth techniques are already in industrial production, starting with a semiconductor-grade as well as an electronic-grade feedstock material. The Staebler–Wronski effect which causes the optically induced degradation of a-Si solar cells is based upon the recombination effect of carriers generated by light in the material. For a high a-Si cell efficiency, the intrinsic layer which is the active part of the solar cell device must have a low defect density and low impurity contamination in order to provide good carrier lifetime.
