title: Dielectric screening of excitons and trions in single-layer MoS2.
abstract: 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 better understand the tightly bound exciton properties in strongly quantum-confined systems and provide a simple approach to the selective and separate generation of excitons or trions with potential applications in excitonic interconnects and valleytronics.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Yuxuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Xi
authors.initials: X
authors.lastname: Ling
authors.forename: Lili
authors.initials: L
authors.lastname: Yu
authors.forename: Shengxi
authors.initials: S
authors.lastname: Huang
authors.forename: Allen L
authors.initials: AL
authors.lastname: Hsu
authors.forename: Yi-Hsien
authors.initials: YH
authors.lastname: Lee
authors.forename: Jing
authors.initials: J
authors.lastname: Kong
authors.forename: Mildred S
authors.initials: MS
authors.lastname: Dresselhaus
authors.forename: Tomás
authors.initials: T
authors.lastname: Palacios
mesh_terms: D004220:Disulfides / Q000737:chemistry*; D004553:Electric Conductivity; D049449:Luminescence; D049408:Luminescent Agents / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry
chemical_list: D004220:Disulfides; D049408:Luminescent Agents; D012997:Solvents; D008982:Molybdenum; C082964:molybdenum disulfide
keywords: Transition metal dichalcogenides; binding energy; dielectric screening; exciton; molybdenum disulfide; photoluminescence