Electron microscopy study of the carbon-induced 2H–3R–1T phase transition of MoS2

Abstract

Phase transition of molybdenum disulfide (MoS₂) was carried out in a pure monocrystal using a combination milling and heating process. Decanoic acid was used as a carbon source to promote the exfoliation of the layers of the material. By Raman spectroscopy, the monocrystal was analyzed showing only the 2H phase. In addition, the atomic structure of the phase was confirmed by atomic resolution microscopy (ARM). The phase transformation was confirmed by X-ray photoelectron spectroscopy (XPS) showing the characteristic displacement in the Mo3d region due to the 1T phase while the S2p region shows a possible interaction between the sulfur and carbon. The ARM images show the characteristics structures of the 1T and 3R phases of MoS₂.