High Phosphorus-doped Seed Layer in Microcrystalline Silicon Oxide Front Contact Layers for Silicon Heterojunction Solar Cells
Chen-Wei Peng1, Chao Lei2, Jun Zhong1, Miao Yang1, Wei Long1, Cao Yu1, Jingquan Zhang2, Yuanmin Li1, Xixiang Xu1
1Chengdu Zhufeng Yongming Technology Co., Ltd., Chengdu, China
/2College of Material Science and Engineering, Sichuan University, Chengdu, China

In this paper, we investigated the application of n-type hydrogenated microcrystalline silicon oxide (n-μc-SiOx:H) as the front surface field (FSF) to improve the short-circuit current density (JSC) of silicon heterojunction (SHJ) solar cells. The advantage of employing n-μc-SiOx:H layer is due to its low optical absorption coefficient and tunable refractive index. However, the SHJ solar cell performance was otherwise limited by the amorphous oxygen alloyed silicon-based films which probably deteriorate the incubation stage of the n-μc-SiOx:H layer. To reduce amorphous/microcrystalline mixture phase during the growth, we implemented high phosphorus-doped seed layer deposited prior to n-μc-SiOx:H layer with refractive indices in the range of 2.7 to 2.9. Finally, optimization of the n-μc-SiOx:H layer led to a conversion efficiency of 23.9%, with JSC of 39.1mA/cm2, open circuit voltage (VOC) of 740mV, and fill factor (FF) of 82.6%.