Stable magnesium zinc oxide by reactive Co-Sputtering for CdTe-based solar cells
Stable magnesium zinc oxide by reactive Co-Sputtering for CdTe-based solar cells
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DOI：
10.1016/j.solmat.2020.110521
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发表时间：
2020-06
影响因子：
6.9
通讯作者：
Yegor Samoilenko;G. Yeung;A. Munshi;A. Abbas;Carey Reich;Michael Walker;Matthew O. Reese;A. Zakutayev;J. Walls;W. Sampath;C. Wolden
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文献类型：
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作者：
Yegor Samoilenko;G. Yeung;A. Munshi;A. Abbas;Carey Reich;Michael Walker;Matthew O. Reese;A. Zakutayev;J. Walls;W. Sampath;C. Wolden
氧化镁锌 (MZO) 是一种很有前景的 CdTe 太阳能电池前接触材料。由于其带隙比传统 CdS 更高，MZO 可以减少寄生吸收，从而显着增加短路电流密度，同时还可以通过 Mg:Zn 比例优化来提供导带偏移调节的优点。 MZO 已成功应用于 CdTe 器件，但其稳定性一直受到关注。 MZO 稳定性问题归因于 CdTe 器件加工环境中存在氧气，导致电流密度-电压曲线中出现双二极管行为 (S-kink)。在这里，我们报告了通过反应共溅射沉积的 MZO 薄膜。反应共溅射 MZO 薄膜具有令人鼓舞的稳定性，通过开尔文探针测量，表面功函数在 6 个月内没有显着变化。多个研究设施的设备处理环境中无论是否存在氧气，都实现了约 16% 的能量转换效率。通过调整薄膜沉积和器件加工参数，特别是通过优化背接触，应该可以进一步提高这些效率。
Magnesium zinc oxide (MZO) is a promising front contact material for CdTe solar cells. Due to its higher band gap than traditional CdS, MZO can reduce parasitic absorption to significantly increase short-circuit current density while also providing a benefit of conduction band offset tuning through Mg:Zn ratio optimization. MZO has been successfully implemented into CdTe devices, however its stability has been of concern. The MZO stability issue has been attributed to the presence of oxygen in the CdTe device processing ambient, leading to double-diode behavior (S-kink) in the current density-voltage curves. Here we report on MZO thin films deposited by reactive co-sputtering. The reactively co-sputtered MZO thin films have encouraging stability, show no significant variation in work function of the surface over a period of 6 months, as measured by Kelvin probe. Energy conversion efficiencies of around 16% have been achieved both with and without presence of oxygen in device processing ambients across multiple research facilities. These efficiencies should be possible to increase further by tuning of the thin film deposition and device processing parameters, especially through optimization of the back contact.