Microstructure of hydrogenated amorphous silicon layers studied by Spectroscopic Ellipsometry for the surface passivation in heterojunction solar cells

The defect scatter interval (S
_t
) of a-Si:H/c-Si interface and void concentration (C
_v
) of a-Si:H were analyzed by Spectroscopic Ellipsometry (S
_E
). The passivation performance of a-Si:H layers in SHJ solar cells was not only affected by the conductivity, but more importantly, it was strongly governed by the hydrogen content (C
_H
) in a-Si:H layers. In addition, the microstructure deduced from SE was in perfect accordance with the results revealed by TEM technique. Then, an implied open circuit voltage (V
_oc
,i
_m
) of 732mV was obtained when S
_t
was about 7fs and CH around 7 at.%.