Defect passivation induced strong photoluminescence enhancement of rhombic monolayer MoS sub(2)

Growing high quality monolayer MoS sub(2) with strong photoluminescence (PL) is essential to produce light-emitting devices on the atomic scale. In this study we show that rhombic monolayer MoS sub(2) with PL intensity 8 times stronger than those of chemical vapour deposition (CVD)-grown triangular and mechanically exfoliated (ME) monolayer MoS sub(2) can be prepared by using CVD. Both Raman and PL measurements indicate low density of defects in rhombic monolayer MoS sub(2) with enhanced PL intensity. Density functional theory (DFT) calculations show that passivation of defects in MoS sub(2) removes trapping gap states, which may finally result in PL enhancement.