Fig. 2: Electrical control of the IX emission.

a Contour plot for the PL spectra of IXs upon cyclic V_g. The white dashed lines serve as guides to the eye. Black arrows mark the peak positions of the IXs at 0 V with different scanning sequences. b, c Photon energy and PL intensity of the IX emission as a function of V_g. d PL spectra of the IXs at 0 V with different scanning sequences. 0V-1, 0V-2, and 0V-3 represent three spectra marked in a. The 0V-2 spectrum is fitted by two Gaussian peaks. The purple and pink lines are attributed to the spin-singlet state (IX^S) and spin-triplet state (IX^T) of interlayer excitons, respectively. The sample was excited by a 532 nm laser with 23 μW power at 78 K. e, f Schematic of the spin-triplet and spin-singlet excitons. Chemical-doped electrons lift the Fermi level up and shift the IX^S to IX^T. When those electrons are released, the IX^T return to IX^S. The orange dashed line stands for the upper spin-splitting conduction band (CB) of WS₂. Red and blue arrows represent the recombination paths of the IXs.