Alternative designs for nanocrystalline silicon solar cells

We discuss the use of two alternative design techniques for enhancing the performance of nanocrystalline Si solar cells. The first technique involves the use of alternating layers of nanocrystalline and amorphous silicon, where the amorphous silicon layer is used to effectively passivate the grain boundaries in nano Si. We show that the use of amorphous Si layer increases photon absorption and leads to higher quantum efficiency in infrared wavelength. The second design involves enhancing the grains in nano Si by growing at higher temperatures, followed by anneal in a hydrogen plasma to preserve grain boundary passivation. This technique results in significant improvement in infrared quantum efficiency of solar cells while preserving good electronic properties.