Advances in amorphous silicon solar cells

Abstract

In amorphous silicon solar cells, there has been noticeable progress in recent years by utilizing new materials such as amorphous silicon carbide (a-SiC:H), microcrystalline silicon (/spl mu/c-Si) and amorphous silicon-germanium (a-SiGe:H). Using the numerical simulator, the function of a p(/spl mu/c-Si) layer in the p-i-n a-Si:H solar cell front contact is examined. Analysis of a double window layer with an inserted p(a-SiC:H) layer and accompanying i(a-SiC:H) buffer layer in the ZnO/p(/spl mu/c-Si)-i-n structure shows that the buffer layer beneficially affects the J/sub SC/ and FF and furthermore, the insertion of a few nanometers thick p(a-SiC:H) additionally improves the solar cell performance. For the a-SiGe:H p-i-n cell, which is used in multibandgap stacked solar cell structures, simulations show that the band-gap grading inside a a-SiGe:H p-i-n cell should assist in the collection of generated carriers at the contacts and should avoid abrupt band-gap discontinuities at the p-i and i-n interface.