Manufacture of different oxides with high uniformity for copper zinc tin sulfide (CZTS) based solar cells

Abstract

Herein, we investigate different oxides layers: Zinc Oxide (ZnO), Nickel Oxide (NiO), Titanium Oxide (TiO₂), and Copper Oxide (CuO), which are effective materials for Copper Zinc Tin Sulfide (CZTS) based solar cells due to their excellent electrical and optical properties. The different oxide films were prepared using spray pyrolysis as a low-cost technique. Then, the films were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and UV-Visible to examine different properties. The XRD pattern showed that the different oxides are polycrystalline. ZnO exhibits a hexagonal wurtzite structure, and NiO is cubic. For the TiO₂, (101) and (004) peaks have been identified, corresponding to the tetragonal anatase phase. CuO showed diffraction peaks corresponding to the monoclinic structures. The SEM results revealed that the deposited films consist of crystals with low crystallinity for NiO and good crystallinity for the rest oxides. The band gap was calculated from the UV-visible measurement. We obtained 3.26 eV, 3.34 eV, 3.2 eV, and 1.7 eV for ZnO, NiO, TiO₂, and CuO respectively. The performance of the CZTS-based solar cell was checked by using the simulator SCAPS. ZnO and TiO₂ were used as window layers where CZTS efficiencies are 24.40% and 24.54%, respectively. These findings show that ZnO and TiO₂ films can be produced by low-cost techniques such as spray pyrolysis to be used as windows and electron transport layers for CZTS-based solar cells.

Keywords: CZTS; Optical properties; Oxide; Spray pyrolysis; Structural; XRD.