Application of Porous a-Si:H Passivation Layer Deposited Using Si2H6 Precursor in Silicon Heterojunction Solar Cells

The improved silicon heterojunction solar cell efficiency by employing porous a-Si:H passivation layer deposited using Si
₂
H
₆
precursor is presented. By introducing Si
₂
H
₆
precursor into the commonly-used SiH
₄
plasma, it is demonstrated that the porosity of a-Si:H passivation layer can be increased significantly. A stack of the porous a-Si:H passivation layer with overlying dense a-Si:H capping layer preserves excellent interface passivation even after doped layer deposition. In the finished solar cell, improvements in V
_OC
from 0.691 to 0.714 V and efficiency from 20.0 to 21.0% were obtained as a consequence of using porous a-Si:H passivation layer deposited under high Si
₂
H
₆
concentration.