Atomic scale study for the structural transformation of single layered MoS2
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.