Fig. 1. Time-resolved spectroscopic measurement system as well as its spectroscopic characterization. (a) Schematic illustration of femtosecond transient absorption spectroscopy system; (b) laser spectrum of pump pulse; (c) cross-correlation trace of pump and probe pulses

Fig. 2. Static spectroscopic characterization of multilayer MoS₂. (a) Static absorption spectrum of multilayer MoS₂ collected at 77K with schematic illustration of energy levels at K valley of multilayer MoS₂ shown in inset; (b) Raman spectrum of multilayer MoS₂ excited by 532 nm laser

Fig. 3. Transient absorption spectra of multilayer MoS₂. (a) 2D map of transient spectra of multilayer MoS₂ in the time delay range of -200 fs--5 ps; (b) transient absorption spectra at 500 fs, 1.0 ps, 1.5 ps, 3.0 ps and 5.0 ps; (c) dynamic curve for A exciton transition corresponding to 618 nm probe wavelength

Fig. 4. Temporal evolution of exciton resonance wavelength position of multilayer MoS₂ versus pump power. <λ⁽¹⁾(t)> of (a) X_A and (b) X_B excitons versus pump power; initial wavelength positions at 50 fs and final wavelength positions at 2 ps of (c) X_A and (d) X_B excitons versus pump power; bi-exponential function fitting results of <λ⁽¹⁾(t)> of (e) X_A and (f) X_B excitons versus pump power

Fig. 5. Temporal evolution of exciton resonance wavelength position of multilayer MoS₂ versus sample temperature. <λ⁽¹⁾(t)> of (a) X_A and (b) X_B excitons versus sample temperature; initial wavelength positions at 50 fs and final wavelength positions at 2 ps of (c) X_A and (d) X_B excitons versus sample temperature; bi-exponential function fitting results of <λ⁽¹⁾(t)> of (e) X_A and (f) X_B excitons versus sample temperature