Low-Temperature Photoluminescence Properties of the Monolayer MoS2 Nanomaterals

In this study, it is shown that with the increase of the number of layers of ultrathin MoS2 nanomaterials, the spacing of Raman shift increased and the photoluminescence intensity decreased. The monolayer MoS2 nanomaterials had the strongest photoluminescence intensity due to the rapid decrease of electron relaxation rate. With decreasing of temperature, the intensity emission enhanced and had a blue shift gradually. At the temperature of 79 K, the bound exciton luminescence peak was found, which was caused by the defect of the contact surface of the MoS2 and the SiO2/Si substrate or the impurities on the surface of the sample.