PHOTONIC AND OPTOELECTRONIC DEVICES BASED ON TWO-DIMENSIONAL TRANSITIONAL METAL DICHALCOGENIDE HETEROSTRUCTURES

Abstract

Optical devices based on two-dimensional (2D) materials have experienced significant growth over the past decade. 2D Transition Metal Dichalcogenide (TMD) materials have been considered as the enabling components for optical emitters and photodetectors on the silicon photonic platform. Micro-disk optical cavities have been made from layered hexagonal boron nitride (h-BN) and 2D TMD semiconductors. The exciton and trion emissions of monolayer TMD are localized in whispering gallery modes with quality factor of up to 1800. We demonstrate that the h-BN/TMD/h-BN cavity can serve as optical light source that is compatible with the silicon platform. Van der Waals heterostructures have also been investigated as photodetectors on the silicon platform. It is found that trilayer architecture of WSe₂/BP/MoS₂, as well as WSe₂/WS₂/MoS₂, exhibit effective spatial segregation of electrons and holes with extended recombination lifetimes (up to 4350 ps for WSe₂/WS₂/MoS₂). The WSe₂/WS₂/MoS₂ photodetector demonstrates high photoresponsivity of 56 mA/W.