超薄氧化硅与氮化钛复合层对光生电子导出的作用

Effect of Ultrathin Silicon Oxide and Titanium Nitride Composite Layer on Photogenerated Electron Export

采用湿法化学氧化和直流磁控溅射制备了超薄氧化硅(a-SiO)和高电子浓度的氮化钛(TiN)复合薄膜,研究其对半导体-准绝缘体-半导体(SQIS)光伏器件中晶硅表面的钝化作用。实验结果表明:相对于铝背场电极,该光伏器件的光电转换效率相对提高了20.72%。结合少子寿命测量和AFORS-HET模拟软件分析,揭示了开路电压增加的原因。aSiO/TiN与n-Si有2.28 eV的价带偏移,可以减缓空穴在背部界面的复合,使复合速率降为原先的1/10,从而有效增加开路电压,达到提高异质结器件光电转换效率的目的,为SQIS光伏器件提供了一种工艺简单、制备成本低的背部钝化接触复合材料。

Ultrathin silicon oxide(a-SiOx)and titanium nitride(TiN)composite film with high electron concentration has been prepared by wet chemical oxidation and direct current magnetron sputtering,and its passivation effect on the crystalline silicon surface in semiconductor-quasi-insulator-semiconductor(SQIS)photovoltaic devices is investigated.The experimental results show that the power conversion efficiency of the photovoltaic device is relatively increased by 20.72%compared with that of the aluminum back field electrode.The reason for the increase of open-circuit voltage is analyzed by combining the minority carrier lifetime measurement and AFORS-HET simulation software.Ultrathin a-SiOx/TiN and nSi have a valence band off of 2.28 eV,which can slow down the recombination of holes on the rear interface and reduce the recombination rate to 1/10 of the original value,thereby effectively increases the open-circuit voltage and achieves the purpose of improving the power conversion efficiency of heterojunction devices.Therefore,the rear passivation contact composite material with simple process and low cost is beneficial for SQIS photovoltaic devices.