E’’ Raman Mode in Thermal Strain-Fractured CVD-MoS2

Molybdenum disulfide (MoS2) has recently attracted considerable interests due to its unique properties and potential applications. Chemical vapor deposition (CVD) method is used widely to grow large-area and high-quality MoS2single crystals. Here, we report our investigation on thermal strain-fractured (SF) single crystalline MoS2, oxidation-fractured MoS2, and normal MoS2by atomic force microscopy (AFM), Raman and photoluminescence (PL) measurements. Several new Raman modes are observed for SF-MoS2. The band gap of SF-MoS2is enlarged by 150 meV and the PL intensity is reduced substantially. These results imply that a structural transformation occurs in SF-MoS2. Our findings here are useful for the design of MoS2-based nanocatalysts with relative high catalytic activity.Keywords:thermal strain-fractured MoS2;defect;Raman spectrum;photoluminescence spectrum;structural transformation