Photoluminescence characterization of the grain boundary thermal stability in chemical vapor deposition grown WS2 (original) (raw)

Materials Research Express, 2017

Abstract

Monolayer transition metal dichalcogenides (TMDs) such as MoS2 and WS2 have been considered as promising candidate materials in nanophotonic applications. However, the structure stability of TMDs based optoelectronic devices is highly sensitive to the working environment. Here we present a successive photoluminescence study of the thermal stability characterization of grain boundary in chemical vapor deposition grown monolayer WS2. Results show that PL intensity enhancement in grain boundaries can be significantly weakened during the annealing process. Transformation temperature starts around 210 °C, substantially lower than the surrounding non-grain-boundary area. First-principle calculations results show that the PL quenching of grain boundaries is caused by the increased structural defects induced by annealing process, which makes the transition of electrons more difficult. Our results provide a route for characterizing the structure stability of two dimensional (2D) semiconductors, calling for extra attention to nanophotonic device working condition.

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