Research on properties of SnS films prepared by constant-potential cathodic electrodeposition

SnS films were cathodically electrodeposited on ITO glass substrates from aqueous solution containing SnSO4 and Na2S2O3 with pH = 2.7 and [Sn2+]/[S2O3]= 1/5 by varying the deposition potential (E) from -0.60 to -1.1V vs SCE. The experiments showed that the near stoichiometric SnS films were synthesized at - 0.72 ∼ - 0.75 V vs SCE. The SnS films were characterized by X-ray diffractograms, microstructure and composition analysis, and their optical and electrical properties were studied. The SnS film has polycrystalline with orthorhombic structure, and has good uniformity with small grain size. Its direct band gap was estimated to be l.31 eV from the optical measurement, close to the bandgap of bulk SnS (1.30 eV). The film had p-type conductivity with an electrical resistivity of the order of 10-3 Ω·cm.