Investigations on the Properties of Nanostructured Mg-Doped Sn₂S₃ Thin Films towards Photovoltaic Applications

This paper reports the synthesis, crystal structure, surface morphology, optical and electrical properties of Mg-doped Sn₂S₃ thin films deposited by spray pyrolysis technique. All the films exhibit orthorhombic crystal structure with a (211) preferential orientation. Crystallite size calculations based on the Debye-Scherrer formula indicated that the Sn₂S₃ crystallite size increases with Mg content from 27.97 nm to 33.58 nm. Scanning electron microscopy images showed that all the films were very smooth composed of nanoneedle and nanoplate shaped grains. The band gap energy of the films exhibits a blue shift from 1.94 eV to 2.09 eV with increase in Mg concentration. Resistivity values of the undoped and Mg-doped Sn₂S₃ films were found to be in the order of 0.1 Ωcm. From the obtained results it is observed that the Sn₂S₃ film coated with 2 wt% Mg concentration exhibits better physical properties