Al2O3与SnO2对碲化镉太阳能电池前电极的界面钝化作用

doi:10.3969/j.issn.0253-2778.2020.04.009

中国科学技术大学学报 ›› 2020, Vol. 50 ›› Issue (4): 450-456.DOI: 10.3969/j.issn.0253-2778.2020.04.009

Al2O3与SnO2对碲化镉太阳能电池前电极的界面钝化作用

郑根华，王东明，吴玲玲，王光伟，蔡彦博，王德亮

中国科学技术大学合肥微尺度物质科学国家研究中心，安徽合肥 230026

收稿日期:2019-12-24 修回日期:2020-03-29 接受日期:2020-03-29 出版日期:2020-04-30 发布日期:2020-03-29
通讯作者: 王德亮
作者简介:郑根华，男，1993年生，硕士. 研究方向：半导体薄膜与器件. E-mail：zghno1@mail.ustc.edu.cn
基金资助:
国家自然科学基金（61774140，61474103）资助.

Interface passivation by Al2O3 and SnO2 at the CdTe solar cell front contact

ZHENG Genhua, WANG Dongming, WU Lingling, WANG Guangwei, CAI Yanbo, WANG Deliang

Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China

Received:2019-12-24 Revised:2020-03-29 Accepted:2020-03-29 Online:2020-04-30 Published:2020-03-29

摘要/Abstract

摘要： 采用磁控溅射法分别生长Al2O3和SnO2，将其作为MgxZn1-xO(MZO)/CdTe薄膜太阳能电池前电极钝化层进行了相关研究.时间分辨光致发光(TRPL)光谱的测试结果显示，MZO/Al2O3/CdTe的少子寿命远大于MZO/CdTe的少子寿命，表明Al2O3对CdTe太阳能电池具有较好的钝化作用. 实验发现，以Al2O3为钝化层的电池亮态电流密度-电压曲线出现了严重的“S-kink”现象. 通过X射线光电子能谱(XPS)分析不同钝化层电池界面的能带匹配，发现Al2O3和CdTe界面较高的导带带阶是造成亮态电流密度-电压曲线出现“S-kink”的主要原因之一. SnO2和CdTe界面处具有较小的导带带阶，通过控制SnO2薄膜厚度，可以利用量子尺寸效应调整SnO2和CdTe界面处的导带带阶，减弱电流密度-电压曲线的“S-kink”现象，提升电池填充因子和短路电流密度，使得电池转化效率提升至9.7%.研究结果表明，较大的导带带阶是导致“S-kink”产生的主要原因，适当降低导带带阶，能有效改善“S-kink”现象，进而有效地提升电池转化效率.

关键词: 碲化镉, 薄膜太阳能电池, 钝化, 能带调制

Abstract: Al2O3 and SnO2 thin layers employed as the passivation layer for MgxZn1-xO(MZO)/CdTe thin-film solar cells were grown by RF magnetron sputtering. Time-resolved photoluminescence (TRPL)spectroscopy spectra show that the minority carrier lifetime of the MZO/Al2O3/CdTe structure is much longer than that of the MZO/CdTe structure, indicating that Al2O3 has a strong passivation effect on CdTe. However, the CdTe solar cells with Al2O3 as the passivation layer demonstrate serious “S-kink” in the light current density-voltage curves. The band alignment of solar cells with different passivation layer were analyzed by X-ray photoelectron spectroscopy (XPS). The large conduction band offset between Al2O3 and CdTe was found to be responsible for the “S-kink” for the solar cells with Al2O3. By controlling the thickness of the SnO2 layer, quantum size effect can be used to adjust the conduction band offset between SnO2 and CdTe, thus reducing the “S-kink” phenomenon, improving the filling factor and short-circuit current density. A solar cell with an efficiency of 9.7% has been fabricated. This study demonstrates that large conduction band offset is the main reason for the “S-kink” in the J-V curves, and that reducing the conduction band offset can effectively decrease the “S-kink” phenomenon and increase the solar cell efficiency.

Key words: CdTe, thin film solar cells, passivation, band alignment

中图分类号:

TM914.42

郑根华，王东明，吴玲玲，王光伟，蔡彦博，王德亮. Al2O3与SnO2对碲化镉太阳能电池前电极的界面钝化作用[J]. 中国科学技术大学学报, 2020, 50(4): 450-456.

ZHENG Genhua, WANG Dongming, WU Lingling, WANG Guangwei, CAI Yanbo, WANG Deliang. Interface passivation by Al2O3 and SnO2 at the CdTe solar cell front contact[J]. Journal of University of Science and Technology of China, 2020, 50(4): 450-456.

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Al2O3与SnO2对碲化镉太阳能电池前电极的界面钝化作用

Interface passivation by Al2O3 and SnO2 at the CdTe solar cell front contact

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