Fig. 3. PL of interlayer excitons under increased optical excitation power.

a Gate-dependent PL spectra of device D1 with the optical excitation power of 50 µW and photon energy centered at 1.959 eV. b Integrated interlayer exciton PL intensity as a function of gate voltage for device D1 with 50 µW (blue) and 5 µW (red) optical excitation power. Dashed lines are fillings determined from the insulating states from the MIM measurements. c, d Gate-dependent PL spectra for device D2 under the optical excitation power of 0.5 and 300 µW. All data are taken at 4.2 K.