Controlling the Anionic Ratio and Gradient in Kesterite Technology
Jacob Andrade‐Arvizu, Robert Fonoll‐Rubio, Víctor Izquierdo‐Roca, Ignacio Becerril‐Romero, Diouldé Sylla, Pedro Vidal‐Fuentes, Zacharie Jehl Li‐Kao, Angélica Thomere, Sergio Giraldo, Kunal J. Tiwari, Shahaboddin Resalati, Maxim Guc, Marcel Placidi
Abstract
kesterite absorbers, and a series of characterizations are performed to understand the anionic redistribution within the absorbers. For identical processing conditions, different Se incorporation dynamics is identified for Sn- and Ge-based kesterites, leading to a homogeneous or graded composition in depth. It is first demonstrated that for Sn-based kesterite the anionic composition can be perfectly controlled through the thicknesses ratio of the sulfide and selenide absorber parts. Then, it is demonstrated that for Ge-based kesterite an anionic (Se-S) gradient is obtained and that by adjusting the processing conditions the composition at the back side can be finely tuned. This technique represents an innovative approach that will help to improve the compositional reproducibility and determine a band gap grading strategy pathway for kesterites. Furthermore, due to its simplicity and reliability, the proposed methodology could be extended to other chalcogenide materials.