Dark I-VCharacteristics and Carrier Transport Mechanism in Nano-Crystalline Silicon Thin Film/Crystalline Silicon Hetero-Junction Solar Cells

N nc-Si/c-Si heterojunction solar cells were prepared with the hot-wire chemical vapor deposition technique.The dark I-V characteristics of the cells with different atomic hydrogen treatments on the c-Si surface were measured.At room temperature,the I-Vcurves were fitted by a two-diode model in which four different voltage regions were recognized:the shunt resistance (V＜0.15),nonideal diode (0.15＜V＜0.3V),ideal diode (0.3＜V＜0.5V),and series resistance (V＞0.5V) regions.The modeled results show that the ideality factor of the nonideal diode (n2) is decreased by a suitable atomic hydrogen treatment of 30s,indicating a lower recombination current and a better interface property.The dark I-V characteristics in the temperature range of 282~335K indicate that in the lower voltage range of 0.15~0.3V,the dark current mainly originates from the recombination current in the depletion region.In the 0.3~0.5V range,the tunneling process dominates in the transport mechanism,which can be described by an interfacial tunneling process through the interface states.