OPTICAL PROPERTIES OF 2D TRANSITION METAL DICHALCOGENIDES ENHANCED BY PLASMONIC NANOSTRUCTURES

As a typical two dimensional (2D) materials system, transition metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2) and molybdenum disulfide (MoS2) have impressive properties arising from the atomically-thin nature and have been demonstrated to be potentially useful building blocks for optoelectronic integrated circuits. An important research focus on TMDCs is their applications in ultrathin emitters or photodetectors. However, being atomically thin limits light-matter interaction in 2D TMDCs, resulting in low light-to-light or light-to-electron conversion efficiency. In this thesis, we significantly improved the light-to-light conversion efficiency in WSe2 via enhancing its photoluminescence (PL) and second harmonic generation (SHG) by gold plasmonic nanostructure with sub-20 nm-wide trenches. Additionally, we investigated the physics process of light-to-electron conversion in MoS2 on graphene by transient absorption spectroscopy. These interesting phenomena of PL, SHG and photoelectron originating from light-matter interaction in TMDCs were systematically investigated in this thesis, facilitating the integrating of these materials in photonic and optoelectronic devices.

Author dc:creator

• WANG ZHUO

• 2D materials, plasmonics, sub-20 nm-wide trenches, photoluminescence, second harmonic generation, carrier dynamics