Fig. 3
From: Emerging photoluminescence from the dark-exciton phonon replica in monolayer WSe2
Gate-dependent PL intensity of the dark-exciton and its replica. a PL spectra at 4.2 K as a function of the top gate voltage for a second BN encapsulated monolayer WSe2 device. The color represents the PL intensity. The excitation is a CW laser centered at 1.959 eV with an excitation power of 40 µW, under which the biexciton (XX) and the charged biexciton (XX−) are also visible. The gate dependence of the dark exciton replica \({\mathrm{X}}_{\mathrm{D}}^{\mathrm{R}}\) is similar to that of the dark exciton. b The line traces from (a) for the gate voltages of 1.0 V (blue), −1.0 V (magenta) and −4.0 V (purple). c Integrated PL intensity for different exciton complexes as a function of the gate voltage. The non-zero PL intensity regions for the dark exciton and its replica are almost identical, from ~−2.1 V to ~0.9 V of the top gate voltage
