Portal de Periódicos da CAPES

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

2014; American Chemical Society; Volume: 14; Issue: 10 Linguagem: Inglês

10.1021/nl501988y

1530-6992

Yuxuan Lin, Xi Ling, Lili Yu, Shengxi Huang, Allen Hsu, Yi‐Hsien Lee, Jing Kong, M. S. Dresselhaus, Tomás Palacios,

Advanced biosensing and bioanalysis techniques

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.