Elemental doping in vdW gap of 2D SnS2 and its evaluation using X-ray absorption spectroscopy
Abhijeet Shelke1*, K. H. Chen1, H. T. Wang1, P. L. Yadav1, I. Shown2, A. Sabbah2, J. W. Chiou3, L. C. Chen2, W. F. Pong1
1Department of Physics, Tamkang University, Tamsui, Taiwan
2Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
3Department of Applied Physics, National University of Kaohsiung, Kaohsiung, Taiwan
* Presenter:Abhijeet Shelke, email:abhijeetshelke15@gmail.com
Recently, 2D layered metal dichalcogenides are attains much attraction of today’s researchers as its novel physical properties unlike to the graphene. Elemental doping into the van der Waals (vdW) gap of 2D layered metal dichalcogenides to engineering the electronic properties is a direct strategy to develop the efficient candidate for several application. Here, 2D layered SnS2 was modified by doping 3d (Cu and V) and 4d (Ag and Mo) elements. The X-ray absorption spectroscopy was used to investigate effect of doping onto the local electronic structure of SnS2. Among the various doping states, V-doped SnS2 exhibit some interesting features at the pre edge (1s → 3d forbidden transition) and absorption edge feature (1s to 4p dipole allowed transition). Therefore, different doping level of V into 2D SnS2 is used for further detailed investigation. The increased intensity along with small chemical shift at higher energies suggests that site symmetry for V and S is reduced due to broken inversion symmetry in disordered VS6 octahedron. Hence broken inversion symmetry observed in V-doped SnS2 samples reduces the weak vdW force between adjacent 2D SnS2 layer. Additionally, at higher V doping, merged absorption edge feature indicates that dense binding of inner 3d and 4s levels to the outermost 4p levels which perturbed by change in valence state. Also, higher level doping reduces the repulsive interaction between another electron by promoting the 1s electron attracting to the nucleus in 2D SnS2 unit cell.

Keywords: 2D layered Materials, Elemental doping, XAS, Electronic structure