Role of substrate temperature on spray pyrolysed metastable π-SnS thin films

We report the synthesis of π-SnS thin films using a pneumatic chemical spray pyrolysis technique. The substrate temperature was varied in the range 300–400 °C to optimise the suitable growth condition and to investigate its effect on the phase stability of π-SnS. X-ray diffraction (XRD) pattern indicated the formation of π-SnS with a lattice constant of a = 11.59 Å. Films deposited at a substrate temperature of 325 °C exhibited higher crystallinity with a larger crystallite size. Besides that, the phase formation of π-SnS was confirmed using Raman spectroscopy vibrational modes. The direct optical band gap varied from 1.61 to 1.82 eV with the variation of substrate temperature. Needle shaped grain morphology was obtained in the scanning electron microscopy (SEM) micrographs. The defects present in the as-deposited films are determined using Photoluminescence (PL) spectra. Hall measurement studies showed that thin films has an n-type conductivity with resistivity in the range 10–103 Ωcm and mobility of the carriers 0.47–1.97 cm²/V with the variation of substrate temperature.