Near-field spectral mapping of individual exciton complexes of monolayer WS2correlated with local defects and charge population

• DOI: 10.1039/c6nr08813a
• Publication Date: 2017-01-13T07:53:42Z
• Authors: Yongjun Lee; Seok Joon Yun; Youngbum Kim; Min Su Kim; Gang Hee Han; A. K. Sood; Jeongyong Kim
• Keywords: Trion; Biexciton; Tungsten disulfide

Exciton transitions are mostly responsible for the optical properties of transition metal dichalcogenide monolayers (1L-TMDs). Extensive studies and structural characterization indicated that presence local defects charge population critically influence exciton emissions 1L-TMDs. However, due to large variations sample experimental conditions, exact mechanism emission influenced by is not clearly understood. In this work using near-field scanning imaging spectroscopy, we directly visualized spatially- spectrally-resolved profiles excitons, trions defect bound excitons in CVD-grown monolayer tungsten disulfide (1L-WS2) with ∼70 nm spatial resolution. We found spatially uniform while was strongly modulated features such as wrinkles. also visually observe a strong correlation between accumulation trion formation upon increased photo-excitation.