Ultrafast Transient Terahertz Conductivity of Monolayer MoS<sub>2</sub> and WSe<sub>2</sub> Grown by Chemical Vapor Deposition

We have measured ultrafast charge carrier dynamics in monolayers and trilayers of the transition metal dichalcogenides MoS<sub>2</sub> and WSe<sub>2</sub> using a combination of time-resolved photoluminescence and terahertz spectroscopy. We recorded a photoconductivity and photoluminescence response time of just 350 fs from CVD-grown monolayer MoS<sub>2</sub>, and 1 ps from trilayer MoS<sub>2</sub> and monolayer WSe<sub>2</sub>. Our results indicate the potential of these materials as high-speed optoelectronic materials.