Fig. 3: Mechanism of the excitonic hysteresis.
From: Nonvolatile electrical switching of optical and valleytronic properties of interlayer excitons
a Contour plot for the PL spectra of monolayer WSe2 as a function of cyclic Vg. The spectra were acquired in the individual WSe2 region of the HS on a hydrophilic substrate. b Contour plot for the PL spectra of monolayer WSe2 on a hydrophobic substrate, which is functionalized by hexamethyldisilazane (HDMS). The PL measurements were conducted at 78 K with 532 nm laser excitation (23 μW). c Illustration of chemical doping caused by O2/H2O molecules. The electronic density of states (DOS) reflect the electron energy distribution around the oxidation potential (Eox) and reduction potential (Ered), respectively. Eredox is the energy where the DOS of reducing and oxidizing species are equal: Dox(Eredox) = Dred(Eredox).
