title: Anomalous excitonic resonance Raman effects in few-layered MoS2.
abstract: The resonance effects on the Raman spectra from 5 to 900 cm(-1) of few-layered MoS2 thin films up to 14-layers were investigated by using six excitation energies. For the main first-order Raman peaks, the intensity maximum occurs at ∼2.8 eV for single layered and at ∼2.5 eV for few-layered MoS2, which correspond to the band-gap energy. At the excitation energy of 1.96 eV, several anomalous behaviors are observed. Many second-order peaks are anomalously enhanced even though the main first-order peaks are not enhanced. In the low-frequency region (<100 cm(-1)), a broad peak centered at ∼38 cm(-1) and its second order peak at 76 cm(-1) appear for the excitation energy of 1.96 eV. These anomalous resonance effects are interpreted as occuring due to the strong resonance with excitons or exciton-polaritons.
authors.affiliation: Department of Physics, Sogang University, Seoul 121-742, Korea. hcheong@sogang.ac.kr.
authors.forename: Jae-Ung
authors.initials: JU
authors.lastname: Lee
authors.forename: Jaesung
authors.initials: J
authors.lastname: Park
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Son
authors.forename: Hyeonsik
authors.initials: H
authors.lastname: Cheong