Industrial‐Scale Preparation of Nanocrystalline n‐Type Silicon Oxide Front Contacts Using N₂O as an Oxygen Source for High‐Efficiency Silicon Heterojunction Solar Cells

ABSTRACT The advantage of employing an n‐type hydrogenated nanocrystalline silicon oxide (nc‐SiO x :H) layer as the front surface field (FSF) in silicon heterojunction (SHJ) solar cells is due to its low optical absorption coefficient and tunable refractive index. However, carbon dioxide (CO 2 ) gas, one of the major precursor gases in the nc‐SiO x :H layer, deteriorates the crystallinity, which is one of the key factors affecting cell performance. Here, we successfully deposited a nc‐SiO x :H FSF layer with high crystallinity for SHJ solar cells by using nitrous oxide (N 2 O) as an alternative oxygen source instead of existing CO 2 . Compared with the use of CO 2 , the use of N 2 O as an oxygen source can achieve a 10% ~ 15% increase in the deposition rate of the nc‐SiO x :H layer, which can shorten the total processing tact‐time, thus having the potential to reduce production costs in large‐scale industrial applications. The influence of N 2 O as an oxygen source on the film properties was also investigated. By optimizing the proportion of N 2 O in the precursor gases, we finally fabricated 274.5 cm 2 ‐area SHJ solar cells with an in‐house average efficiency of 25.76%, which is approximately 0.1% abs higher than that of their reference counterparts (using CO 2 as an oxygen source), and obtained a certified efficiency of 25.79% for the champion cell independently confirmed by the ISFH CalTeC in Germany.