Tuning the properties of MoS₂ flakes with gold nanoparticles and Rhodamine dye

Pooneh Farhat, The University of Western Ontario

Abstract

Transition Metal Dichalcogenides (TMDs) are remarkable due to their distinct physical and chemical characteristics when the number of layers is changed. When interfaced with metal nanoparticles, these hybrid materials such as MoS₂-Au nanoparticles exhibit enhanced properties that can be used for applications such as in sensing, catalysis, and photovoltaics devices by enhancing their signals and tuning their physical properties. Also, 2D MoS₂ can be a useful platform as a SERS substrate for organic molecules detection, including Rhodamine 6G (R6G) as a photosensitizer in MoS₂ devices.

In this thesis, MoS₂ flakes were prepared using the chemical vapor deposition (CVD) technique on SiO₂/Si substrates. Tip-Enhanced Raman Spectroscopy was used to investigate the effect of varying MoS₂ thicknesses on Raman modes. Raspberry-like gold nanoparticles and R6G molecules were coated on MoS₂ flakes to investigate the plasmon-exciton and dye effect respectively, on Raman and photoluminescence enhancements using tip-enhanced scattering and contact potential difference microscopy.