Fig. 2
Interlayer excitons. a False color contour plot of the EL spectra as a function of bias voltage for sample B1 without monolayer hBN spacer. b EL spectra for biases in the range of Vb = 2.0–2.2 V extracted from (a). The spectra are vertically shifted for clarity. The inset in panel (b) shows the peak position of the IX as a function of bias for five different samples and linear fits to the dependencies. The gray dashed line marks the energy of 1.08 eV, which is an estimation for the energy of a presumptive IX without electrically injected carriers. We obtain this value by using threshold voltages of ~0.6–0.7 V (red shaded area) for measurable carrier injection extracted from photoluminescence and reflectance contrast measurements (see Supplementary Note 4)
