Fig. 3. Screening of Coulomb interactions by charge carriers.
a Transient absorption map of monolayer MoS2 as a function of probe photon energy and pump-probe delay after photoexcitation at 3.10 eV. b dR/R spectra of a WSe2 monolayer. c Photoinduced optical response of WS2 bilayers. (Left top) Reflectance contrast spectra without pump excitation (RC,0) and 0.4 ps after excitation (RC) by a pump pulse with an applied fluence of 840 μJ/cm2. (Left bottom) Corresponding differential reflectance contrast spectra ΔRC = RC – RC,0. (Right) Reflectance contrast spectra at different time delays after excitation. Figure reproduced with permission from a ref. 56, © 2016 American Chemical Society; b ref. 57, © 2014 IOP Publishing; c ref. 39, © 2015, Springer Nature