Shalvey Thomas P, Bagshaw Heath, Major Jonathan D
Stephenson Institute for Renewable Energy, Department of Physics, University of Liverpool, Liverpool L69 7ZF, U.K.
SEM Shared Research Facility, School of Engineering, University of Liverpool, Liverpool L69 3GL, U.K.
ACS Appl Mater Interfaces. 2022 Sep 21;14(37):42188-42207. doi: 10.1021/acsami.2c07609. Epub 2022 Sep 9.
Recent improvements to the CdTe solar cell device structure have focused on replacing the CdS window layer with a more transparent material to reduce parasitic absorption and increase , as well as incorporating selenium into the absorber layer to achieve a graded band gap. However, altering the CdTe device structure is nontrivial due to the interdependent nature of device processing steps. The choice of the window layer influences the grain structure of the CdTe layer, which in turn can affect the chloride treatment, which itself may contribute to intermixing between the window and absorber layers. This work studies three different device architectures in parallel, allowing for an in-depth comparison of processing conditions for CdTe solar cells grown on CdS, SnO, and CdSe. Direct replacement of the CdS window layer with a wider band gap SnO layer is hindered by poor growth of the absorber, producing highly strained CdTe films and a weak junction. This is alleviated by inserting a CdSe layer between the SnO and CdTe, which improves the growth of CdTe and results in a graded CdSeTe absorber layer. For each substrate, the CdTe deposition rate and postgrowth chloride treatment are systematically varied, highlighting the distinct processing requirements of each device structure.
碲化镉太阳能电池器件结构最近的改进主要集中在使用更透明的材料替代硫化镉窗口层，以减少寄生吸收并增加（此处原文似乎不完整），以及将硒掺入吸收层以实现渐变带隙。然而，由于器件加工步骤相互依存的性质，改变碲化镉器件结构并非易事。窗口层的选择会影响碲化镉层的晶粒结构，这反过来又会影响氯化处理，而氯化处理本身可能会导致窗口层和吸收层之间的混合。这项工作同时研究了三种不同的器件架构，以便深入比较在硫化镉（CdS）、氧化锡（SnO）和硒化镉（CdSe）上生长的碲化镉太阳能电池的加工条件。用带隙更宽的氧化锡层直接替代硫化镉窗口层受到吸收层生长不佳的阻碍，会产生高度应变的碲化镉薄膜和较弱的结。在氧化锡和碲化镉之间插入一层硒化镉可缓解这一问题，这改善了碲化镉的生长并形成渐变的硒化镉碲吸收层。对于每种衬底，系统地改变碲化镉的沉积速率和生长后的氯化处理，突出了每种器件结构独特的加工要求。
