Optical and Structural Studies of Tin Disulfide (SnS2) Synthesized by Facile Hydrothermal Method

Abstract

Transition metal dichalcogenides (TMDCs) have found diverse applications for intrinsic semiconducting and tunable electronic properties mediated via the van der Waals interaction between the adjacent chalcogen planes. Therefore, the large-scale production of TMDCs without compromising the material properties is the major challenge at the present moment. We follow a simple, cost-effective, and environmentally friendly hydrothermal technique for synthesizing tin disulfide (SnS2). The optical properties are investigated using UV-visible, photoluminescence (PL), Raman, and FTIR spectroscopy. The UV-visible absorption spectra of pure SnS2 show a broad absorption peak located at 340 nm, and the corresponding optical band gap energies are estimated to be 2.14 and 4.02 eV, respectively. The PL spectra display a sharp emission peak at 561 nm due to the radiative recombination of bound excitons for the excitation wavelength of 340 nm. FTIR is used to observe the existence of functional groups in the material. The absorption peak observes at 625 cm-1 corresponds to the vibration of the Sn-S bond. From Raman spectra, a sharp peak appears at 314 cm-1, corresponding to the A1g mode of pure SnS2, which occurs due to the out-of-plane stretching vibration of sulfur atoms in the SnS2 material. The XRD is used to identify structural phases. The sharp diffraction peaks at 2Ɵ = 15.17ᴼ and 28.55ᴼ corresponds to (001) and (100) planes, respectively, that suggest the hexagonal phase of pure SnS2. Interplanar spacing is estimated using Bragg’s law, and the value is found to be 5.83 Å. The average crystallite size is estimated to be 28 nm from the Williamson-Hall plot, which is comparable with the crystallite size calculated from Scherrer’s formula.