Novel type of multicrystalline silicon solar cell with an additional electrode along the grain boundaries

The grain boundaries (GBs)in multicrystalline silicon (mc-Si) act as potent ial barriers fur photogenerated carriers. in conventional me-Si solar cells , photo-generated carriers must travel through the GBs before they are coll ected at the grid metal. We investigated new types of solar cells and their characteristics by using a preferential GB etching and by inserting an add itional electrode along the removed GBs. Preferential etching gave a textur ed surface of 2 mu m as well as a deep trench of over 10 mu m along the GBs . By placing an electrode at the GBs, we achieved a short-circuit current d ensity of 15 mA/cm(2) at an input power of 8.9 mW/cm(2) and obtained an eff iciency improvement by 2 %. This paper discusses the GB characteristics and a method to improve the performance of me-Si solar cells.