Preparation and Photoluminescence of Tungsten Disulfide Monolayer

Tungsten disulfide (WS2) monolayer is a direct band gap semiconductor. The growth of WS2monolayer hinders the progress of its investigation. In this paper, we prepared the WS2monolayer through chemical vapor transport deposition. This method makes it easier for the growth of WS2monolayer through the heterogeneous nucleation-and-growth process. The crystal defects introduced by the heterogeneous nucleation could promote the photoluminescence (PL) emission. We observed the strong photoluminescence emission in the WS2monolayer, as well as thermal quenching, and the PL energy redshift as the temperature increases. We attribute the thermal quenching to the energy or charge transfer of the excitons. The redshift is related to the dipole moment of WS2.Keywords:chemical vapor transport deposition;tungsten disulfide;monolayer;photoluminescence