Localized Interlayer Excitons in MoSe2-WSe2 Heterostructures without a Moiré Potential

Interlayer Exciton Diode and Transistor

“…In Figure c, we show polarization resolved PL along the slide to test the feasibility of this architecture for valleytronic applications, pumping with a 1.72 eV laser. The IX PL is primarily cocircularly polarized with the laser excitation (see Figure S1), as seen in previous studies on hBN-separated WSe 2 –MoSe 2 heterostructures. , We note that we observe nearly constant PL polarization of ∼50%, showing that the valley polarization remains intact during induced exciton motion. Figure d shows the spatial dependence of the IX PL with varying pump powers, which shows that high power (∼100 μW) resulting in high IX density and high IX–IX repulsion force is required to realize long-range IX current.…”

“…29−32 In order to increase the mobility of IXs, we suppress the moirépotential by placing a hexagonal boron nitride (hBN) spacer between the TMD layers. 28,33−36 This increases the IX energy from 1.33 to 1.41 eV (Figure S1), and increases the IX dipole moment to 1.1 nm (Figure S2), in excellent agreement with the 0.5 nm bilayer hBN separator layer plus the 0. dipole moment of the IX without the hBN separator, 19,24,36 and allowing for greater tunability of exciton energy via the electric field-dipole moment potential energy. The schematic of the excitonic device is shown in Figure 1a and b, with an optical microscope image of the device in Figure S3.…”

Morphology Deformation and Giant Electronic Band Modulation in Long-Wavelength WS2 Moiré Superlattices

“…This motivates us to give a direct and complete microscopic exploration of the moirémorphology deformation and its correlated electronic band modulation in TMD moireś, which is highly important to fully understand the sample-dependent phenomena observed in different experiments. [1][2][3]34 Here, using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) measurements combined with first-principles calculations we study the moireś tructure deformation and its resulting electronic band modulation in long-wavelength WS 2 superlattices at atomic scale. We image various moirémorphologies with their domain geometry changing from regular hexagons to heavily deformed ones that experience strong structural deformation.…”