Atomic scale study for the structural transformation of single layered MoS2

Abstract

The structural transformation of single and few layered molybdenum disulfide (MoS₂) from 2H to 1T phase was studied at the atomic scale. Single layered MoS₂ was prepared via ultrasonication of an ethanolic dispersion. Bulk MoS₂ was in the 2H phase, which was confirmed via XRD. The reduction of the difference between the characteristic peaks of MoS₂ was observed through Raman spectroscopy for the exfoliated MoS₂. Without adding any other atoms, a phase transformation of MoS₂ was observed. The transformation of the 2H phase MoS₂ to the 1T phase was studied under a high resolution transmission electron microscope (HRTEM). The characteristic honeycomb structure together with the specific pattern of the back-folded edge of MoS₂ confirm the structural transformation. Electron energy loss spectroscopy (EELS) was performed to ascertain the chemical composition of MoS₂.