Extended Data Fig. 7: Calibrated photoluminescence spectra for a comparison of the photoluminescence intensity from heterobilayers with different twist angles.

a–c, Photoluminescence spectra of samples in which θ = 57° (a), 20° (b) and 2° (c). The photoluminescence intensity of samples in which θ = 2° and θ = 57° is about 100 times higher than that of θ = 20°. Excitation powers were 10 nW for a and c and 100 nW for b. The photoluminescence intensity for the heterobilayer in which θ = 20° is still in the linear regime for powers less than 100 nW. Aside from the excitation power, the data from all three twist angles were acquired under identical experimental conditions to facilitate their comparison.