Transforming bilayer MoS2 into single-layer with strong photoluminescence using UV-ozone oxidation

The use of single-layer MoS2 in light emitting devices requires innovative methods to enhance its low photoluminescence (PL) quantum yield. In this work, we report that single-layer MoS2 with a strong PL can be prepared by oxidizing bilayer MoS2 using UV-ozone oxidation. We show that as compared to mechanically-exfoliated single-layer MoS2, the PL intensity of the single-layer MoS2 prepared by UV-ozone oxidation is enhanced by 20–30 times. We demonstrate that the PL intensity of both neutral excitons and trions (charged excitons) can be greatly enhanced in the oxidized MoS2 samples. These results provide novel insights into the PL enhancement of single-layer MoS2.