Characterization of surface and heterointerface of Cu2ZnSn1-xGexSe4 for the solar cell applications
Characterization of surface and heterointerface of Cu2ZnSn1-xGexSe4 for the solar cell applications
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用于太阳能电池应用的 Cu2ZnSn1-xGexSe4 的表面和异质界面表征
DOI：
10.1002/pssr.201900708
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Norio TERADA
中科院分区：
文献类型：
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作者：
Katsuhiko Saito,Yusei Matsuo;Akihiro Tomota;Tatsuki Hamada;Yuken Oishi;Tooru Tanaka,and Qixin Guo;青木 裕介;青木 裕介;青木裕介;西尾勇輝， 阪本竜也， 青木裕介;西尾勇輝・坂本竜也・青木裕介;青木裕介;青木裕介;青木裕介;青木裕介;Tatsuya Sakamoto，Yusuke Aoki;Kazuya Hayashi, Yusuke Aoki;Norio TERADA
本研究以CZTGSe(CZTGSe)和CZTGSe(CZTGSe)的表面电子结构和CZTGSe的Ge/(SnGGSe)组成比X= + 0-1为基础，结合紫外和X射线光电子能谱分析了CZTGSe和CZTGSe的表面电子结构和能带排列。CdS/CZTGSe界面的导带偏移量随x的增加而线性减小，即所谓的尖峰导带连接，而价带偏移量与x无关。此外，CZTGSe表面附近的空穴密度随着INx的增加而增加，这与测量的内置电势随x的增加相对应。然而，尽管有良好的能带对准和较大的界面内建电位，开路电压(VoC)在超过0.2的情况下饱和到≈0.5 V。外量子效率谱分析表明，随着Inx的增大，CZTGSe体载流子复合受到抑制，而CZTGSe表面附近的复合增强。讨论了这些复合中心、电子结构和VOC饱和度之间的关系。
This study analyzes the electronic structure of Cu2ZnSn1–xGexSe4(CZTGSe) surface and band alignments of CdS and CZTGSe using the Ge/(Sn + Ge) composition ratios ofx= 0–1 based on inversed, ultraviolet, and X‐ray photoemission spectroscopy. The conduction band offsets of the CdS/CZTGSe interface linearly decrease with increasingx, which are so‐called spike conduction band connections, whereas the valence band offsets are observed to be independent ofx. Moreover, the hole density near the CZTGSe surface increases with an increase inx; this corresponds to the increase in the measured built‐in‐potential withx. However, the open circuit voltage (VOC) saturates to ≈0.5 V forxover 0.2 in spite of the favorable band alignment and larger built‐in‐potential ofxat the interface. External‐quantum‐efficiency spectral analysis shows that the carrier recombination in CZTGSe bulk is suppressed with an increase inx, whereas the recombination near the CZTGSe surface is enhanced. The relationship between these recombination centers, electronic structure, and saturation ofVOCis discussed.