Silicon heterojunction solar cells with high surface passivation quality realized using amorphous silicon oxide films with epitaxial phase

摘要

The epitaxial growth of the i-layer of crystalline silicon heterojunction solar cells has been widely accepted as harmful to surface passivation. In our experiments, however, although a very rough epitaxial phase in the intrinsic a-Si1-xOx:H passivation layer was confirmed by transmission electron microscopy and spectroscopic ellipsometry, a high effective lifetime and an implied-V-OC of over 720mV were achieved with lifetime samples. The high passivation quality was confirmed by the obtained open circuit voltages of 728 and 721 mV for n- and p-type solar cells, respectively, with an a-Si1-xOx:H/p-mu c-Si1-xOx:H stack rear structure. These results indicate that, contrary to the common knowledge, high surface passivation quality can be achieved even when the epitaxial phase is present. (C) 2015 The Japan Society of Applied Physics