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

We report the synthesis of pi-SnS thin films using a pneumatic chemical spray pyrolysis technique. The substrate temperature was varied in the range 300-400 degrees C to optimise the suitable growth condition and to investigate its effect on the phase stability of pi-SnS. X-ray diffraction (XRD) pattern indicated the formation of pi-SnS with a lattice constant of a = 11.59 angstrom. Films deposited at a substrate temperature of 325 degrees C exhibited higher crystallinity with a larger crystallite size. Besides that, the phase formation of pi-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 Omega cm and mobility of the carriers 0.47-1.97 cm(2)/V with the variation of substrate temperature.