Unraveling interface characteristics of Zn(O,S)/Cu(In,Ga)Se2 at nanoscale: Enhanced hole transport by tuning band offsets
Unraveling interface characteristics of Zn(O,S)/Cu(In,Ga)Se2 at nanoscale: Enhanced hole transport by tuning band offsets
复制标题
DOI：
10.1016/j.apsusc.2019.144782
复制
发表时间：
2020-04
影响因子：
6.7
通讯作者：
Juran Kim;Jayeong Kim;Eunji Ko;H. Park;Seokhyun Yoon;Dae‐Hyung Cho;Woontae Lee;Yong‐Duck Chung;W. Jo
中科院分区：
文献类型：
--
作者：
Juran Kim;Jayeong Kim;Eunji Ko;H. Park;Seokhyun Yoon;Dae‐Hyung Cho;Woontae Lee;Yong‐Duck Chung;W. Jo
环境友好型Cu(In,Ga)Se2（CIGS）太阳能电池需要用无毒材料替换含cd的缓冲液。Zn（O，S）缓冲材料已经开发出来，其效率甚至比cds缓冲的CIGS薄膜太阳能电池更高[23.35%,Ref.[6]]。本文研究了Zn（O，S）和CIGS界面的波段偏移。在1.0%、1.3%和1.6%的氧气分压下沉积无cd缓冲层。利用微拉曼散射光谱和开尔文探针力显微镜研究了氧分压对器件结构和电子性能的影响。我们在吸收器和缓冲器之间的界面上实现了空间功函数映射的深度剖面。效率最高的样品，使用1.3%的氧气生长，显示出80 mV的峰状带偏移。我们提出可以通过调整界面处的波段偏移以及改进吸收器和缓冲材料来提高效率。
Environment-friendly Cu(In,Ga)Se2(CIGS) solar cells requires the replacement of Cd-containing buffers with non-toxic materials. Zn(O,S) buffers have been developed and yielded even better efficiency than CdS-buffered CIGS thin-film solar cells [23.35%, Ref. [6]]. In this work, we studied band offsets of Zn(O,S) and CIGS interfaces. The Cd-free buffer layers were deposited with 1.0%, 1.3%, and 1.6% oxygen (O2) gas partial pressure during the deposition. Effects of the oxygen partial pressure on the structure and electronic properties of the devices were investigated by micro-Raman scattering spectroscopy and Kelvin probe force microscopy, respectively. We achieved depth-profiling of spatial work function mapping across the interface between the absorbers and the buffers. The best efficiency sample, grown using 1.3% of oxygen, showed 80 mV spike-like band offsets. We propose that the efficiency can be improved through tailoring of the band offsets at the interface as well as improving the absorber and the buffer materials.