Aboulfadl Hisham, Keller Jan, Larsen Jes, Thuvander Mattias, Riekehr Lars, Edoff Marika, Platzer-Björkman Charlotte
Department of Physics,Chalmers University of Technology,41296 Göteborg,Sweden.
Department of Engineering Sciences,Uppsala University,75236 Uppsala,Sweden.
Microsc Microanal. 2019 Apr;25(2):532-538. doi: 10.1017/S1431927619000151. Epub 2019 Mar 11.
Surface sulfurization of Cu(In,Ga)Se2 (CIGSe) absorbers is a commonly applied technique to improve the conversion efficiency of the corresponding solar cells, via increasing the bandgap towards the heterojunction. However, the resulting device performance is understood to be highly dependent on the thermodynamic stability of the chalcogenide structure at the upper region of the absorber. The present investigation provides a high-resolution chemical analysis, using energy dispersive X-ray spectrometry and laser-pulsed atom probe tomography, to determine the sulfur incorporation and chemical re-distribution in the absorber material. The post-sulfurization treatment was performed by exposing the CIGSe surface to elemental sulfur vapor for 20 min at 500°C. Two distinct sulfur-rich phases were found at the surface of the absorber exhibiting a layered structure showing In-rich and Ga-rich zones, respectively. Furthermore, sulfur atoms were found to segregate at the absorber grain boundaries showing concentrations up to ~7 at% with traces of diffusion outwards into the grain interior.
对Cu(In,Ga)Se2（CIGSe）吸收层进行表面硫化是一种常用技术，可通过提高异质结的带隙来提高相应太阳能电池的转换效率。然而，人们认为最终的器件性能高度依赖于吸收层上部区域硫族化物结构的热力学稳定性。本研究采用能量色散X射线光谱法和激光脉冲原子探针断层扫描技术进行高分辨率化学分析，以确定吸收层材料中的硫掺入情况和化学再分布。硫化后处理是通过在500°C下将CIGSe表面暴露于元素硫蒸气中20分钟来进行的。在吸收层表面发现了两个不同的富硫相，呈现出分层结构，分别显示出富铟区和富镓区。此外，还发现硫原子在吸收层晶界处偏析，浓度高达约7原子%，并有微量向外扩散到晶粒内部。
