Defect Engineering in Cu2ZnSnSe4 Solar Cells via Controlled Selenization

This research investigates the impact of reaction pathways on the defect concentration and material properties of Cu2ZnSnSe4 (CZTSe) thin films. A sputtering technique was employed to deposit CuxSe and ZnxSn1-x precursor layers. Subsequently, the temperature of a low-temperature annealing step was precisely controlled to influence the reaction pathway towards CZTSe formation. This approach enabled a systematic study of the interplay between annealing temperature, reaction pathway, and the resulting material properties. The findings demonstrate that manipulating the annealing temperature effectively influences the reaction pathway, leading to variations in the morphology, crystal structure, compositional uniformity, and defect concentration within the CZTSe absorber layer. Notably, this approach can suppress Sn loss and the formation of the detrimental ZnSe phase. This study provides valuable insights into the intricate relationship between processing conditions, defect formation, and the resulting material properties in CZTSe thin films. These findings are crucial for developing strategies to mitigate detrimental defects and optimize the performance of CZTSe-based solar cells. Furthermore, this research paves the way for innovative approaches to address the current limitations of CZTSe technology and accelerate the development of high-efficiency solar energy solutions.