Synthesis of CZTS kesterite by pH adjustment in order to improve the performance of CZTS thin film for photovoltaic applications

Abstract

[EN] Quaternary CZTS (Cu2ZnSnS4) kesterite thin layers were successfully made by electrochemical deposition method. CZTS thin layers were deposited on Indium Tin Oxide (ITO) from an aqueous solution. In this work, the effects of pH adjustment under ambient conditions of CZTS thin films were studied. The as grown samples were investigated by numerous existing characterization systems. The X-ray diffraction (XRD) proves the polycrystalline description of the layer. The average crystallite size is varying from 10 nm to 24 nm of the films is dependent on the pH of the solution. All the thin films are in the CZTS kesterite phase attributed to A(1) mode at 334 cm(-1) verified by Raman spectroscopy. The SEM and AFM study show that the pH variation of the so-lution improved the surface morphology and topography of the CZTS thin films which increase several nm in grain size. Moreover, the optical analysis indicates a suitable band gap in the range of 1.5-1.8 eV depending upon the sulfurization temperature. It is found that the pH variation affects both the stability and the performance of the high-quality CZTS absorber layer applications. The CZTS layer with 4.80 pH was annealed at 450 degrees C and 500 degrees C, and at these temperatures the band gap was varied. At the end the band gap variations effect on the performance of CZTS based solar cell is being analyzed by using a simulation tool SCAPS-1D.