Fig. 4: Integrated PL intensity of bare excitons and exciton-polaritons as a function of temperature.
From: Brightening of a dark monolayer semiconductor via strong light-matter coupling in a cavity
a Temperature-dependent emission intensity of bare excitons in pristine WSe2 monolayer. The experimental data are shown as green circles, and the corresponding integration regions are marked as dashed boxes in Fig. 3a–c. The solid curve represents the result of a theoretical modelling (see main text). The mechanism of PL intensity for different temperature ranges is shown as insets: thermal activation (10–200 K) and relaxation into momentum-forbidden dark states (200–270 K). b Temperature-dependent PL emission intensity of exciton-polaritons. The experimental data of the ground state and first excited state are shown as blue squares and red diamonds, respectively. The integration region of the ground state (first excited state) is indicated with a dashed (dotted) box in Fig. 3g–i. The solid curves are fits of the theory model. The strong PL intensity at low temperatures evidences the brightening effect of intrinsically dark exciton. The error bars are obtained by comparing the signal intensity to the standard deviation of the background noise.
