Fabrication of CZTS thin films by dip coating technique for solar cell applications

Abstract

Phase pure Cu2ZnSnS4 thin films were fabricated by simple dip coating technique. Precursor films were coated onto glass substrates using stable solutions of copper, zinc and tin dissolved in 2 methoxyethanol and monoethanolamine. These precursor films were sulphurized in N2+H2S atmosphere at different temperatures ranging from 400°C to 600°C. XRD analysis and Raman studies revealed a single CZTS phase for the films sulphurised at 500°C and 550°C, but good crystallinity was observed for the film sulphurized at 550°C. Rietveld method was used for structural refinement. SEM and FESEM studies indicate good surface morphology and large grains in the film sulphurized at 550°C. The film exhibited an optical absorption coefficient of >104cm−1 and an optical band gap of 1.4eV. The carrier concentration, resistivity and mobility are 1.434×1018cm−3, 5.3cm2/Vs and 0.828Ωcm, respectively and the conduction is p-type. The photovoltaic properties are suitable for thin film solar cell fabrication.