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人工晶体学报 ›› 2023, Vol. 52 ›› Issue (3): 460-466.

• 研究论文 • 上一篇    下一篇

少量锗的加入对铜锌锡硒薄膜及其器件性能的影响

余纳, 许从艳, 李秋莲, 陈玉飞, 赵永刚, 周志能, 杨鑫, 王书荣   

  1. 云南师范大学,云南省农村能源工程重点实验室,昆明 650500
  • 收稿日期:2022-11-25 出版日期:2023-03-15 发布日期:2023-04-06
  • 通信作者: 杨 鑫,博士,副教授。E-mail:yangxinzju@qq.com
    王书荣,博士,教授。E-mail:shrw88@aliyun.com
  • 作者简介:余 纳(1997—),女,云南省人,硕士研究生。E-mail:2932477712@qq.com
  • 基金资助:
    国家自然科学基金(61941401,U1902218)

Effect of a Small Amount of Ge on the Properties of Cu2ZnSnSe4 Thin Films and Devices

YU Na, XU Congyan, LI Qiulian, CHEN Yufei, ZHAO Yonggang, ZHOU Zhineng, YANG Xin, WANG Shurong   

  1. Key Laboratory of Rural Energy Engineering in Yunnan, Yunnan Normal University, Kunming 650500, China
  • Received:2022-11-25 Online:2023-03-15 Published:2023-04-06

摘要: 本文采用溶液法制备铜锌锡硒(Cu2ZnSnSe4, CZTSe)薄膜。通过在溶液中加入少量的锗(Ge),探究Ge的引入对CZTSe薄膜及其器件性能的影响。为了对比分析,分别制备了不含Ge的CZTSe和含少量Ge的铜锌锡锗硒[Cu2Zn(Sn,Ge)Se4,CZTGSe]两组薄膜及其薄膜太阳电池。分别利用X射线衍射仪(XRD)、拉曼(Raman)光谱、扫描电子显微镜(SEM)、霍尔(Hall)测试、电流-电压(J-V)曲线和外量子效率(EQE)测试等手段对吸收层薄膜的晶体结构、相的纯度、表面形貌、载流子浓度,以及完整器件的电学性能进行表征和分析。结果表明,在CZTSe薄膜中引入少量Ge可以与Se形成液体流动剂,提升吸收层薄膜结晶度,改善晶体质量,减少晶界数量,降低光生载流子在晶界处的复合,提高载流子寿命。此外,Ge对Sn的部分取代可以降低与Sn有关的缺陷态密度,增加带隙,提高开路电压,同时改善串联电阻和并联电阻,提高填充因子。最终获得了开路电压为513.2 mV、短路电流为27.47 mA/cm2、填充因子为62.68%、光电转换效率为8.83%的CZTGSe薄膜太阳电池。

关键词: 铜锌锡硒薄膜, 薄膜太阳电池, Ge, 溶液法, 硒化处理, 光电转换效率

Abstract: In this paper, Cu2ZnSnSe4(CZTSe) thin films were prepared by solution method. A small amount of Ge was added into the solution and the effect of Ge incorporation on the properties of CZTSe thin films and devices was investigated. For comparison, two sets of CZTSe thin films and corresponding solar cells, namely CZTSe without Ge and CZTSe with a small amount of Ge [Cu2Zn(Sn, Ge)Se4, CZTGSe] were prepared. The crystal structure, phase purity, surface morphology, and carrier concentration of the prepared thin films, as well as the electrical properties of the complete devices were characterized and analyzed by X-ray diffractometer (XRD), Raman spectra, scanning electron microscopy (SEM), Hall measure system, current voltage (J-V) curve, and external quantum efficiency (EQE) tests, respectively. The results demonstrate that Ge incorporation into the CZTSe film promotes the crystallization mainly due to the formation of Ge-Se liquid flux during the selenization process, reduces the number of grain boundaries and the minority carriers recombination at the grain boundaries and enhances the carrier lifetime. In addition, partial substitution of Ge for Sn reduces the density of defect states associated with Sn, increases the energy band gap and open circuit voltage, improves the series and parallel resistance, and thus increases the fill factor. Finally, the prepared CZTGSe thin film solar cells reach a photoelectric conversion efficiency of 8.83% with open circuit voltage of 513.2 mV, short circuit current of 27.47 mA/cm2 and fill factor of 62.68%.

Key words: Cu2ZnSnSe4 thin film, thin film solar cell, Ge, solution method, selenization, photoelectric conversion efficiency

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