Fig. 1. Emergence of deeply bound exciton satellites.
a Optical image of electrostatic gating device composed of exfoliated monolayer WSe2 (red area) encapsulated in hBN with graphite backgate (outlined in black). Scale bar is 10 µm. b Schematic of sample side view. c Photoluminescence as a function of back gate voltage with the laser spot indicated by the red dot in a. Three satellites peaks near 1.60 eV appear when the sample is n-doped. d Spatial map of the integrated PL from the satellite peaks at Vb = 0.5 V. Integration spectral region shown by arrows on top of c, and spatial region outlined by dashed white lines in a. e Spatial map of the peak energy of the highest-energy satellite at Vb = 0.5 V. f Waterfall plot of PL spectra from three different samples, showing homogeneous satellite binding energies and robust three peak spectral features. The energy axis is scaled relative to the free neutral exciton (X0 at ~1.735 eV).