Semiconducting two-dimensional material (S2DM) has potential applications in optoelectrical devices and energy technology. Enhancing the optical properties and tuning the band gap of the S2DM is useful for different applications such as light emitting diodes, sensors, and solar cells. Plasmonic nanoparticle, such as those made of gold or silver, can enhance the radiative electronic transitions, such as the photoluminescence (PL) of a fluorophore, when located in the domain of the plasmon field. Silver nanotetrahedron (AgNT) arrays of three different wall lengths were prepared on the surface of a glass substrate by an overgrowth of silver nanodisks monolayer. AgNT arrays are used to enhance the optoelectrical properties of the semiconducting 2DM such as MoS2. The optical absorption is collected for individual MoS2 using hyperspectral high-resolution optical spectroscopy (1) while placed on top of the AgNT arrays and (2) on the surface of the glass substrate. The three typical optical spectral features of MoS2 were observed clearly in both cases, in addition, an extra peak was observed for the AgNT. A considerable enhancement of the photoluminescence (PL) of the MoS2 is observed when measured on the top of the AgNT arrays that followed a direct correlation with its size. Raman spectrum collected for the individual MoS2 sheets on top of the AgNT arrays showed a great enhancement compared with that obtained in the absence of plasmonic nanoparticles. The plasmon field of the AgNT is responsible for the enhancement of the Raman signal of MoS2. Additionally, there is a direct correlation between the Raman enhancement factor and the plasmon field intensity calculated by the finite difference time domain (FDTD).

Enhancing the optical properties of semiconducting 2D materials by plasmonic nanoparticle 2D arrays

2019 Spring National Meeting

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