Effects of sulfurization temperature on CZTS thin film solar cell performances

• Development of CZTS solar cells using elemental metal sputtering.
• Reported efficiency of 5.75%.
• 112-Oriented CZTS films with well-defined morphology obtained.
• 550 °C found to be optimum temperature for CZTS growth.
• CZTS films exhibit near-optimum bandgap ∼1.5 eV.

Synthesis of Cu2ZnSnS4 thin film solar cells by sulfurization of sputtered Sn/Zn/Cu precursors is studied. The sulfurization temperatures were varied, and the morphology, cross section, and composition of the CZTS were investigated by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and Raman scattering. To further explore the CZTS layer, the following additional layers were deposited to complete the solar cells: CdS with chemical bath deposition; ZnO and AZO with RF magnetron deposition; and, finally, silver fingers as the front contact. The efficiency and characteristics of the thin film solar cells were measured and a detailed comparison is reported. Sulfurization at 550 °C yields a maximum efficiency of 5.75% without any anti-reflective layers.