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

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 degrees 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 10(17) cm(-3), a sheet resistivity of similar to 0.4 Omega cm and a Hall mobility of similar to 3 cm(2)/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 10(4) cm(-1). These results suggest that the annealed copper nickel tin sulfide thin films at these relatively low temperatures (300 degrees C) in a nitrogen atmosphere for 1 h are very suitable for low-cost photovoltaic applications.