Annealing Effects on Cu₂ZnSnSe₄ Thin Films: Structural, Electrical, and Optical Characterization

This study aims to explore the effects of annealing on the structural, electrical, and optical properties of Cu₂ZnSnSe₄ thin films fabricated by thermal evaporation. Results obtained from SEM equipped with EDAX, XRD, and Raman analysis revealed that CZTSe thin films were successfully obtained. Depending on the annealing temperature, increasing grain size and shifting from spherically shaped grains to rod-shaped particles were observed. The room temperature resistivity decreased with increasing annealing temperature, exhibiting values of 44.10 Ω-cm, 2.61 Ω-cm, and 3.08 Ω-cm for films annealed at 400 °C, 500 °C, and 600 °C, respectively. Carrier concentrations of the same samples obtained from Hall Effect measurements were observed as 5.13x1015 cm-3, 3.07x1017 cm-3, and 1.09x1017 cm-3 with p-type conductivity. The as-deposited and annealed thin films exhibited optical band gap values of 1.98 eV, 1.78 eV, 1.35 eV, and 1.65 eV, respectively.