Synthesis and characterization of Cu-based selenide photovoltaic materials: Cu2FeSnSe4 and Cu(In, Al)Se2
Synthesis and characterization of Cu-based selenide photovoltaic materials: Cu2FeSnSe4 and Cu(In, Al)Se2
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DOI：
10.1016/j.jallcom.2015.05.044
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发表时间：
2015-09
影响因子：
6.2
通讯作者：
Xiankuan Meng;H. Cao;H. Deng;Wenliang Zhou;J. Tao;Lin Sun;F. Yue;P. Yang;J. Chu
中科院分区：
文献类型：
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作者：
Xiankuan Meng;H. Cao;H. Deng;Wenliang Zhou;J. Tao;Lin Sun;F. Yue;P. Yang;J. Chu
采用射频磁控溅射和快速热处理工艺制备了两种铜基硒化物半导体Cu_2FeSnSe_4（CFTSe）和Cu（In，Al）Se_2（CIAS）。对于CFTSe，在460至520 °C范围内的升高的硒化温度导致阳离子-阴离子键长的缩短趋势，对应于在硒化过程中释放更多的形成热，这有利于晶粒生长。然而，根据应变计算，在500 °C下硒化的薄膜的晶格应变呈现最小值，意味着薄膜中的缺陷较少。对于另一种铜基材料CIAS，其带隙（Eg）直接由价带到导带的带间电子跃迁决定。Al含量的变化会影响Al-Se的杂化程度，导致导带中电子的重新分布，从而优化导带结构。由于在较高温度下的硒化过程中Al的量较少，导带最小值移动到带隙中。此外，CFTSe和CIAS分别在500和540 °C下硒化时转变为具有大晶粒尺寸和致密形貌的单相。研究了开路电压分别为76 mV和353 mV的CFTSe（Eg = 1.16 eV）和CIAS（Eg = 1.34 eV）的电学性能。
Two Cu-based selenide semiconductors Cu2FeSnSe4(CFTSe) and Cu(In, Al)Se2(CIAS) have been fabricated using radio-frequency magnetron sputtering followed rapid thermal processing. For CFTSe, the elevated selenization temperatures ranging from 460 to 520 °C result in a shortened trend of bond-length of cationic–anionic, corresponding to more formation heat released during the selenization process, which favors the grain growth. However, according to the strain calculation, the lattice strain of the thin film selenized at 500 °C presents a minimum value, meaning the fewer defects in thin films. As for the other Cu-based material CIAS, the band-gap (Eg) is determined by the band-to-band electron transition from valence band to conduction band directly. The Al content will affect the hybridization degree of Al–Se which will drive the redistribution of electrons in the conduction band, and then optimize the band-structure. The conduction band minimum shifts into band-gap due to the less amount of Al during the selenization process at higher temperature. In addition, both of CFTSe and CIAS transform into single-phase with large grain size and dense morphologies when selenized at 500 and 540 °C, respectively. The electrical properties of CFTSe (Eg∼ 1.16 eV) and CIAS (Eg∼ 1.34 eV), which open circuit voltage is 76 mV and 353 mV, respectively, are also researched.