Mixed-Phase nc-SiO_X:H Interlayer to Improve Light Trapping and Shunt Quenching in a-Si:H Solar Cell

By using radio frequency plasma enhanced chemical vapor deposition method (13.56 MHz), a mixed phase nanocrystalline silicon oxide (nc-SiOX:H) interlayer has been developed. The optoelectronic properties of the nc-SiO:H layer was optimized by varying gas flow ratio. An interlayer has been inserted between the silicon layer and back contact. The nc-SiO:H interlayer has served as a dual-function layer in the solar cell, i.e., act as a rear reflector layer for light trapping and also minimized the local leakage and quenching the shunt effect. The fabricated solar cells with and without nc-SiOX:H interlayer showed efficiencies of 7.84% and 9.35%, respectively, with an i-layer thickness of 250 nm. Efficient light trapping and suppressed parasitic losses by adopting nc-SiOX:H interlayer resulted in a relative increase in the efficiency of about 19.26%. Light-induced degradation study of the solar cells with and without an interlayer has also been presented here. After shunt quenching effect, the relative degradation in conversion efficiency for an interlayer cell is ~7.27% after 1000 h of light soaking, whereas, under the same experimental conditions, the relative degradation is ~10.82% for the solar cell without an interlayer. The possible origin of higher degradation in the latter device has been addressed in this work.