Temperature-dependent properties of monolayer MoS2 annealed in an Ar diluted S atmosphere: an experimental and first-principles study

Abstract

In this work, the effects of annealing temperature on the structural and optical properties of monolayer MoS₂ were examined in detail based on experimental and theoretical studies. The monolayer MoS₂ was annealed in an argon diluted sulfur atmosphere at temperatures in the range of 800–860 °C. The annealed monolayer MoS₂ showed a continuous enhancement in photoluminescence (PL) intensity with annealing temperature up to 850 °C. The mechanism of the variation in the PL properties of MoS₂ was proposed to be due to the combined effects of tension release by generation of triangular pits on the MoS₂ surface, and p-type doping in the monolayer MoS₂. Theoretically, the formation of triangular pits with the same Mo-zz edge structure as the as-prepared MoS₂ was demonstrated by first-principles calculations.