Widening Bandgap of i/n-a-Si:H Window Layers via Hydrogen Injection in Cat-CVD for SHJ Solar Cells

In this study, we performed post hydrogen treatment separately after the deposition of i/n a-Si:H window layers. The treatment was carried out in Cat-CVD chamber by inletting hydrogen gas and driving the dissociated atomic hydrogen into the layers by thermal irradiation. Owing to the increased Si-H bonds in the films, the defect states reduced and the optical bandgaps widened. This process was applied to silicon heterojunction solar cell fabrication, the cell efficiencies were improved apparently from 22.15% to 22.76% (J
_sc
from 38.0 to 38.2 mA/cm
²
, V
_oc
from 728.4 mV to 735.3 mV, FF from 80.0% to 81.1%).