Study of the Temperature-Dependence of Exciton Lifetime in Single-Layer WSe$_{2}$

Two-dimensional layered transition metal dichalcogenides (TMD) have recently received much attention because of their distinctive optical properties, including their strong excitonic interactions and the tightly bound trion states that they support. In this paper, we report the results of time-resolved photoluminescence measurements on exfoliated monolayer samples of WSe$_{2}$. The lifetime and quantum efficiencies of different emission features, including those from neutral and charged excitons, were found to display a strong temperature dependence over the range of 10-300K. We discuss the results in terms of the structure of the conduction band near the K-point and of the possible roles of different exciton states.