Evolution of structural and morphological characteristics of MoS₂ thin films with nitrogen doping

The two-dimensional MoS₂ coatings with incomplete head triangles, triangular stars and six-blade stars domain shape have been grown by the CVD method on SiO₂/Si and Si substrates and then doped with nitrogen. The shape of MoS₂ domains showed remarkable changes after N₂ doping. Doping dramatically changed the physical properties of MoS₂ coatings. An accurate study was carried out on the prepared MoS₂ thin films using optical microscopy, atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy. The X-ray spectrum showed well-defined MoS₂ coatings with a strong (103) preferred orientation of a typical hexagonal structure. There were no changes in crystallographic orientations after nitrogen doping, while the peak intensity declined. Raman spectroscopy specified that MoS₂ multilayer was proved by Raman frequency difference between two characteristic modes (E_2g¹ and A_1g). The position and intensity of Raman modes exhibited sensitivity to nitrogen doping. The AFM results indicated topography and roughness variations with nitrogen doping.