研究目的
To study tungsten diselenide (WSe2) and tungsten disulfide (WS2) monolayer materials in second harmonic generation spectroscopy and microscopy experiments, providing dispersion data and absolute values for χ(2) within a photon energy range of 2.3–3.2 eV.
研究成果
The study provided dispersion data and absolute values for χ(2) for WSe2 and WS2 monolayers within a photon energy range of 2.3–3.2 eV. Fine spectral features in the dispersion data indicate the impact of near bandgap exciton transitions. The fundamental bandgap and exciton binding energy were determined for both materials, with ranges for the absolute values of the sheet nonlinearity also provided.
研究不足
The study is limited by the spectral range of 2.3–3.2 eV and the resolution of the experimental setup. The adhesion of the WSe2 and WS2 sample layers to the SiO2 surface may affect local fields and thus the values of the second order nonlinearity χ(2).