Optical properties of chemically synthesized SnS₂ nanostructure and study of current transport mechanism in Schottky and heterojunction diodes

SnS₂ nanostructure was prepared by Chemical bath deposition method using sodium sulfide (Na₂S) and tin (IV) chloride hydrate (SnCl₄⋅H₂O) as source of S⁻² and Sn⁺⁴ at different volumetric ratios (Sn/S). XRD pattern of SnS₂ confirms the formation of nanostructure with a hexagonal type of structure. It shows a transformation of nanoparticles into nanosheets when synthesized at higher molar concentration. The absorption edge shows a blue shift that confirms the quantum confinement effect in SnS₂. Both direct and indirect band gaps of SnS₂ are calculated using UV–visible spectroscopy. Photoluminescence indicates the probability of indirect transition and the existence of inherent defects. The electrical properties of SnS₂ are measured in planar geometry show a linear ohmic behavior. The prepared SnS₂ has been used to fabricate Schottky and heterojunction diodes. The ideality factor become less in heterojunction compared to Schottky one with an average barrier height 0.56 eV. The current transport process has been studied in both the fabricated devices that exhibited Richardson Schottky (RS)-type conduction mechanism.