Development of Cu2NiSnS4 based thin film solar cells without a sulfurization step

Abstract Copper nickel tin sulfide thin films were prepared by a low-cost and facile route, using spin-coating deposition technique without a sulfurization step. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive analysis, and Hall-effect measurements were used to analyze the influence of the annealing temperature on the structural, morphological, compositional, optical and electrical properties of the deposited thin films. After annealing at 300 °C in a nitrogen atmosphere for 1 h, the prepared thin films exhibit a pure cubic structure, good morphology without any cracks, and are nearly stoichiometric. The films showed a p-type conductivity with a sheet carrier concentration of 4.5 1017cm−3, a sheet resistivity of ~ 0.4 Ω cm and a Hall mobility of ~ 3 cm2/V.s. On the other hand, optical transmittance measurements of the annealed films revealed an optical gap of 1.35 eV and an absorption coefficient greater than 104 cm−1. These results suggest that the annealed copper nickel tin sulfide thin films at these relatively low temperatures (300 °C) in a nitrogen atmosphere for 1 h are very suitable for low-cost photovoltaic applications.