Fig. 1: Optical characterization of the BL MoS₂.

a Static RC spectra of a ML and BL MoS₂ encapsulated in hBN. RC = (R_sub − R_TMD)/R_sub, where R_TMD is the reflectance of the sample, while R_sub is taken on the substrate. Inset: sketch of the band diagram in MoS₂ BL; the dashed red line indicates the coherent tunneling of holes. b Sketch of the MoS₂ BL encapsulated in hBN (out of scale) measured by pump-probe micro-spectroscopy. c Transient differential reflectivity map as a function of delay time τ and probe photon energy measured for MoS₂ BL. d Dynamic RC of the MoS₂ BL at negative (before pulsed excitation) and positive (after pulsed excitation) delay times, extracted from the differential reflectivity map in c. Solid curves show the Lorentzian fit of the dynamic RC. Black arrows show optical saturation and energy shift of the X_A−BL and hIX transitions, and the photo-induced absorption of the \({{\rm{X}}}_{A-BL}^{*}\) trion. The shaded yellow area displays the energy and bandwidth of the pump pulses. e Normalized exciton peak amplitude variation (ΔA_exc) of X_A−BL and hIX, extracted from the dynamic RC at different time delays.