Electrochemically synthesized microcrystalline tin sulphide thin films: high dielectric stability with lower relaxation time and efficient photochemical and photoelectrochemical properties

Abstract

A detailed study has been carried out on the structural, dielectric and impedance properties of polycrystalline p-type SnS thin films grown on transparent conducting oxide (TCO) coated glass substrates from an aqueous solution of tartaric acid, SnSO₄ and Na₂S₂O₃ by a modified electrochemical technique. The as-deposited films were found to be smooth, almost pinhole free and well adherent to the bottom substrate. X-ray diffraction studies revealed the formation of polycrystalline SnS films with an orthorhombic phase. Field emission scanning electron microscopy and atomic force microscopy revealed a moderately compact surface morphology with evenly distributed almost spherical grains. Optical measurements showed direct band gap energy of 1.5 eV. Detailed electrical (dc and ac) analyses showed the p-type nature of the deposited films with unique dielectric behavior. The band-gap energy, resistivity, dielectric constant and relaxation time make this material and ideal absorber layer, which is also reflected in the efficient photochemical and photoelectrochemical behavior.