Resonant Exciton Scattering Reveals Raman Forbidden Phonon Modes in Layered GeS.

ABSTRACT: Germanium monosulfide with an anisotropic puckered crystalline structure has recently attracted much attention due to its unique optical and electronic properties; however, exciton-phonon interactions were only superficially elucidated. We study the resonant Raman scattering and the photoluminescence of the optically active Γ-exciton in layered GeS flakes and evaluate the exciton and phonon responses on variations in the excitation energy, laser-light and emission polarizations, temperature, and laser power. A double-resonance mechanism allows for observing Raman forbidden (dark) first- and second-order longitudinal-optical phonon modes whose symmetries and energies are moreover calculated by density functional perturbation theory. For (quasi)-resonant exciton excitation, the selection rul

SUBMITTER: Jadczak J 

PROVIDER: S-EPMC10165653 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature