Dielectric Screening of Excitons and Trions in Single-Layer MoS 2

Photoluminescence (PL) properties of single-layer MoS2 are indicated to have strong correlations with the surrounding dielectric environment. Blue shifts of up to 40 meV of exciton or trion PL peaks were observed as a function of the dielectric constant of the environment. These results can be explained by the dielectric screening effect of the Coulomb potential; based on this, a scaling relationship was developed with the extracted electronic band gap and exciton and trion binding energies in good agreement with theoretical estimations. It was also observed that the trion/exciton intensity ratio can be tuned by at least 1 order of magnitude with different dielectric environments. Our findings are helpful to…

• UD
  U.S. Department of Energy

  Award: EFRC-33TEC
• OO
  Office of Naval Research

  Award: ONR/PECASE-6926686
• DO
  Division of Materials Research

  Awards: DMR-1004147, DMR-1231319