TFSI钝化晶体硅表面性质的第一性原理研究

摘要/Abstract

摘要： 晶体硅表面钝化是高效率晶体硅太阳能电池的核心技术,直接影响晶体硅器件的性能。本文采用第一性原理方法研究了一种超强酸-双三氟甲基磺酰亚胺(TFSI)钝化晶体硅(001)表面。研究发现,TFSI的四氧原子结构能够与Si(001)表面Si原子有效成键,吸附能达到-5.124 eV。电子局域函数研究表明,TFSI的O原子与晶体硅表面的Si的成键类型为金属键。由态密度和电荷差分密度分析可知,Si表面原子的电子向TFSI转移,从而有效降低了Si表面的电子复合中心,有利于提高晶体硅的少子寿命。Bader电荷显示,伴随着TFSI钝化晶体硅表面的Si原子,表面Si原子电荷电量减少,而TFSI中的O原子和S原子电荷电量相应增加,进一步证明了TFSI钝化Si表面后的电子转移。该工作为第一性原理方法预测有机强酸钝化晶体硅表面的钝化效果提供了数据支撑。

关键词: 单晶硅, 表面缺陷, 钝化, TFSI, 有机强酸, 第一性原理, 态密度

Abstract: Surface passivation of crystalline silicon is the key technology of high efficiency crystalline silicon solar cells, which directly affects the performance of crystalline silicon devices. In this paper, the surface passivation of crystalline silicon (001) by a superacid bis(trifluoromethane)sulfonimide (TFSI) was studied by first principles method. It is found that the four oxygen atoms of TFSI can effectively bond with Si atoms on Si (001) surface, and the adsorption energy is -5.124 eV. The electron localization function shows that the bonding type between O atom of TFSI and Si on the surface of crystalline silicon is metal bond. The analysis of density of states and charge difference density show that the electrons on the Si surface are transferred to TFSI, which effectively reduces the electron recombination on the Si surface and improves the minority carrier lifetime of crystalline silicon. Bader charge shows that the charge of Si atoms on the surface decreases with the passivation of Si atoms on the surface of crystalline silicon by TFSI, while the charge of O atoms and S atoms in TFSI increases, which further proves the electron transfer after TFSI passivation of Si surface. This work provides data support for the first principle method to predict the passivation effect of organic strong acid passivated crystalline silicon surface.

Key words: single crystal silicon, surface defect, passivation, TFSI, organic acid, first principle, density of state

中图分类号:

O469

魏丽静, 孟子杰, 郭建新. TFSI钝化晶体硅表面性质的第一性原理研究[J]. 人工晶体学报, 2022, 51(1): 72-76.

WEI Lijing, MENG Zijie, GUO Jianxin. First Pricinples Study on TFSI Passivating Surface of Crystal Si[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2022, 51(1): 72-76.

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